Owner: Learning Computer Programming URL:http://learning-computer-programming.blogspot.com Join Date: Tue, 12 Jun 2007 04:07:38 -0500 Rating:0 Site Description: I post articles, tips, tricks, techniques, algorithms etc. related to C++ Programming. Many of the things that I discuss also applies to other programming languages. Site statistics:Click here
Simulating the throw of dice in C++ 2007-06-11 00:51:00 What makes the throw of dice special is the fact that you can’t always guess which number will come up. This property is known as randomness, which is needed in certain types of programs (ex. Games).In this article, we are going to discuss how random numbers are generated and used in C++ with the help of a simple example.The program illustrates generation and use of random numbers in C++: //C++ Program to generate RANDOM NUMBERS //function is isolated so it may be easily //incorporated in other programs //NOTE:stdlib.h header file is required //for using this funtion elsewhere #include<stdio.h> #include<stdlib.h> #include<conio.h> //FUNCTION PROTOTYPE int random(int HighestNumber,int LowestNumber); void main(void) { char ch; puts("Random Number Generator: "); while(ch!='q' && ch!='Q') //loop until q or Q is pressed { puts("Press any key to throw dice..."); ch=getch(); //%d tells the compiler that the value after
String Searching Function in C++ 2007-06-09 23:42:00 Nothing much to say, here I present you with a searching function. It takes
two-character string (array) as the argument and finds the position of the second
string in the first. For example, if the two arrays passed to the function have
the following values:String
1: ”I like C++”
String 2: “C++”then the function will return 7, because as an array, string 1 has the word
C++ starting from the index number 7.If the function cannot find the second string inside first then it will return
the value -1, indicating that the search was unsuccessful.The program below is easy to understand; therefore, I have left it up to you
to understand how it is working.
//C++ program which searches for a substring
//in the main string
#include<stdio.h>
int search(char *string, char *substring);
void main(void)
{
char s1[50], s2[30];
int n;
puts("Enter main string: ");
gets(s1);
puts("Enter substring: ");
gets(s2);
n=search(s1,s2);
if(n!=-1)
{
Sorting an array using Selection Sort 2007-06-09 02:37:00 Sorting is the process by which the elements of a group (ex. Arrays) are arranged
in a specific order (ascending or descending).The process of sorting is very important, since it is needed in many types
of programs. Ex. If you need to arrange the heights of various students in a
class, you need to sort their heights.While there are quite a few methods employed for sorting, we will be discussing
about Selection Sort method in this article.In selection sort, all the elements of an array are compared with the other
elements following it and interchanged so that smaller elements come at the
top.So, what that means is that the first element is compared with the second,
third … elements then the next is selected (second element of the array)
and it is compared with the third, fourth … elements and in this way different
elements are selected serially and compared with elements following it.
Interchange is done so that smaller elements come high up in the array. (for
ascending order)To ma Read more:Sorting
Simple Problems in C++ Part III 2007-06-07 01:58:00 Yesterday I was having a look at my traffic statistics when I came to know
about one thing. I saw that most of the visitors to this blog paying attention
to the two of my recent articles Simple
Problems in C++ Part I and Simple
Problems in C++ part II.
Seeing that, I made up my mind to write the third part of the Problems in C++
series with some more interesting problems. Now, without wasting your time anymore,
I present you with some more Simple problems in C++. Here they are :-
Problem No. 1:
#include<iostream.h>
void main(void)
{
int i=1;
for(;;)
{
cout<<i++;
if (i>10) break;
}
}
QUESTION: Is there any error in the program?
Problem No. 2: #include<iostream.h>
void main(void)
{
int i=1;
while()
{
cout<<i++;
if (i>10) break;
}
}
QUESTION: Is there any error in the program?
Problem No. 3:
#include<iostream.h>
void main(void)
{
int a=10,b=20;
if(!(!a) && a)
Name Abbreviation Program in C++ 2007-06-07 01:53:00 In this article, we are going to design a program that abbreviates the first
and middle name leaving the last name as it is. Suppose if the user inputs the following name:
William Henry GatesThen the output of the program would be:
W. H. GatesWithout further a due I present you with the Steps:-We have declared two character arrays (strings), name[4] and abname[30],
which stores the name input by the user and abbreviated name respectively.
Suppose if the user inputs the following name:
William Henry Gates
Then the two arrays would have the following values:
Name[40]="William Henry Gates" (unchanged)
Abname[30]=EMPTY
The next step is to store the first character of the array name[40] to the
abname[30] array and put a dot (.) and a space( ) after it.
Next, we set-up a loop which finds space in the array name[40] (space separates
first, middle and last names). As soon as a space is detected the character
immediately after the space is stored to the abname[30] array, followed by
a Read more:Program
Learn to Define and Use Functions in C++ 2007-06-06 01:28:00 Functions can be thought of as separate programs that are designed to perform
specific tasks. For example, in a program, separate functions can be so designed
to perform specific tasks such as taking input, doing calculation, giving output
etc.In this article we will be discussing about what functions are and how they
are designed in C++.Generally, programs have many logically different parts (input, output etc.)
which can be coded separately as function. This makes programs easily manageable
and understandable.Suppose we have to design an invoice program that takes input, calculates and
at last displays the output. We have two options to do so, we can either program
the whole thing linearly or we can make separate functions for each of the tasks
(input, output etc.), this would make the program far more manageable and upgradeable.
(In the future, if you need to change certain things, you only need to alter
the functions)In this way if you divide various activities of the program into Read more:Functions
Learn to use Loops in C++ 2007-06-05 01:47:00 While every programming language has its own version of loops (iteration statements),
the loop statements of C++ are way much more powerful than those of other languages.
It is because of the variations that loops can have in C++. This article would
give just an introduction to the loop structures in C++, leaving complex variation
of loops for the coming articles.
A Loop (iteration) statement repeatedly executes a set of statements until
a particular condition is reached.
Have a look at this program:
//C++ program
#include<iostream.h>
void main(void)
{
int arr[3];
cout<<"enter three numbers:"<<endl;
cin>>arr[0]>>arr[1]>>arr[2];
cout<<"number 1: "<<arr[0]<<endl;
cout<<"number 2: "<<arr[1]<<endl;
cout<<"number 3: "<<arr[2]<<endl;
}
Now look at this program:
//C++ program
#include<iostream.h>
void main(void)
{
int arr[3];
cout<<"enter thr Read more:Loops
Learn to use Pointers in C++ 2007-06-04 06:50:00 For those of you who do not know what pointers are, I give you a short definition.
Pointer is a type of variable that stores memory addresses rather than simple
data. Pointers
also have Data Types associated with it, Ex. int pointers can
only store memory address of int variables and similarly float pointers can
only store memory address of float variables.Pointers are one of the most important distinct features of C++. It gives the
programmers power and control over several things.Pointers have many uses; sometimes it is used as the faster means of accessing
arrays while sometimes it is implemented so that the function in C++ can modify
the parameters passed to it.Pointers are extensively used in C++, this might not be obvious to you right
now but as you start programming some complex program, you will notice how important
pointers are.This article would serve as a little introduction to pointers in C++, it would
help you understand what pointers are and how it is used in C++.Declara
Operators in C++ Part II 2007-06-01 23:56:00 In the previous article, we had been discussing about what operators are and
the types of operators in C++. In that article, we discussed till arithmetic
and relational operators, in this article we will continue our discussion with
operators in C++ by moving on to the other types of operators.
Logical Operators
In the previous article, we discussed about relational operators that eastablish
relationships among the operands, logical operators refers to the ways by which
these relationships can be connected.
(Logical OR), && (Logical AND), ! (Logical NOT) are the three types
of logical operators. These are used to combine existing expressions.
The examples below will illustrate the working of each of these operators.
(4<5)(5<4) this expression results in 1 (true), since one of the expression
(first one) is true.
(6<8)&&(4==4) results in 1 (true).
(6<8)&&(4<3) results in 0 (false), because one of the relation
is false.
!(4<8) results in 0 (false).
!(4>1
Operators in C++ Part I 2007-06-01 23:36:00 C++ has a vast range of operators, in fact C++ has greater number of operators
than most other programming languages.
Operators in C++ are divided into categories namely arithmetic, relational,
logical, conditional, bitwise etc. according to the type of operation they perform.
Arithmetic Operators in C++
+, - ,*, /, % are all arithmetic operators. You should not be having any problems
with the first four operators (they have their normal meaning), regarding the
last one, it is known as the Modulus operator. It divides two operands (data,
variable) and gives the remainder of the two upon division.
Increment (++) & Decrement (--) Operators
The increment operator acts on one operator to increase its value by one while
the decrement operator does the opposite.
Prefix (++var) and postfix (var++) are the two types of increment/decrement
operators. Both does the same arithmetic operation to the operand but the value
of the variable in the expression is evaluated differently in different case
Simple Problems in C++ Part II 2007-05-31 22:39:00 Better programmer is he who has better programming skills, for programming
skills one needs to PROGRAM because only reading won’t get you anywhere.
From regular programming comes good programming skill.
Solving problems basically means to write a program which performs the actions
as per the question. But the problems listed here are different; these problems
will check your understanding of the C++ programming language. You don’t
need to write any program.
In this article I have listed some of the good problems that I have come across,
which are related to what we discussed so far (variables, data types etc.).
This article is basically for beginners but even if you are an experience C++
programmer, you might want to look at them.
Problem No. 1
//C++ Program
#include<iostream.h>
void main(void)
{
int arr[5]={2,3};
cout<<arr[2]<<arr[3]<<arr[4];
}
QUESTION: What will be the output of this program?
Problem No.2
//C++ Program
#include Read more:Simple
5 Common C++ Programming Mistakes 2007-05-30 23:16:00 To err is human
It is normal for programmers to make mistakes while learning c++ programming.
Mistakes (or errors) are often caused by misconception in the programmers mind
or by forgetting certain things.
While syntax errors are easier to spot since the c++ compiler shows the related
information but logical errors often remains unnoticed, and many a times the
program works just as fine.
It is not possible to completely eliminate errors by yourself but it is definitely
possible to minimize them as a c++ programmer.
Here I am listing 5 of the common mistakes (errors) that beginners commit (not
sorted in any order).
Mistake No. 1
Have a look at this C++ Program
#include<iostream.h>
void main(void)
{
int base,height,area;
cout<<"Enter the base and height of the triangle:";
cin>>base>>height;
area=0.5*base*height;
cout<<endl<<"AREA:"<<area;
}
Here the variable area is such that sometimes its value would be whole num Read more:Common
, Programming
Simple Problem in C++ 2007-05-29 22:55:00 Interchanging the values of two variables…
What’s the big deal. You take one extra variable; put the first variable’s
value in it, copy the value of the second variable to the first one and then
copy the value of the extra variable to the first one and there you are!
But what, if I say that you don’t have to use the third variable, let’s
say because the memory is full and you are left with memory only sufficient
for storing two variables. Doesn’t make sense. Huh!
It makes sense if you want to gain programming skills because solving problems
is the only way to do it. In this article we start with a simple one.
So, how do we do it?
It is not very big deal to interchange the values of two variables without using
the third variable yet I have come across peoples who don’t think it can
be done.
To solve this problem we need to do two things (i)First we need to write down
the method (algorithm) of doing it (ii0 Secondly, we need to write the c++ code
from the algorithm.
The Read more:Problem
, Simple
Half an Hour to Variables 2007-05-29 00:55:00 I wrote this article yesterday when I was getting bored and was feeling too
lazy, all thanks to the hot weather here. I planned of meeting my friends but
at last I insisted on staying at home when I wrote this. Regarding the title,
I thought that if it took me an hour to write it then you would have to hardly
give Half an Hour to Variables.
Now coming to the serious stuff…
What is Variable
During program run we need to manipulate data and the data to be manipulated
are stored in memory locations known as variable. In the system memory, data
are stored in memory locations such as 0x00243 which are not easy to remember
if we have quite a lot of them. Variables are memory locations having a name
so that different memory locations can be distinguished easily.
Declaration and Initialization of Variables
The declaration of variable generally takes the following form:
type varname;
Here type is any valid data type and varname is the variable name.
Ex.int age;
float temp;
Static initia
C++ Data Types in Detail 2007-05-27 22:21:00 Data types are means to identify the type of data and associated operations
of handling it. C++ provides a predefined set of data types for handling the
data it uses. When variables are declared of a particular data type then the
variable becomes the place where the data is stored and data types is the type
of value(data) stored by that variable.
Data can be of may types such as character, integer, real etc. since the data
to be dealt with are of may types, a programming language must provide different
data types.
In C++ data types are of two types:-
Fundamental Data Types: As the name suggests these are
the atomic or the fundamental data types in C++. Earlier there was five of
these (int, char, float, double and void) but later two new data types namely
bool and wchar_t have been added. Int stores integer data or whole numbers
such as 10, -340 etc., char stores any of the ASCII characters, float is used
to store numbers having fractional part such as 10.097, double stores the
same Read more:Detail
Introduction to C++ Programming 2007-05-21 22:55:00
This article gives you an introduction to C++ Programming
from ground level.
This article won't teach you all the fundas of C++ programming rather it gives
you the base to learn C++ programming, remember that for further learning, the
base should be strong and this is what this article tries to do. It would let
you know many fundas which will help you in further learning of the the language.
C++ was developed in 1980s in the Bell Laboratories by Bjarne Stroustrup as
an object oriented programming language. This language is considered by many
as an extension of the programming language C. The extension of programming
language C to create C++ is obtained by adding classes to C. This is why C++
was initially called “C with Classes”. The C++ programming language
derives its name from the increment operator used in C, which increments the
value of a variable. The symbolic name of C++ rightly indicates that this language
is enhanced version of C.
Features of C++ Programming Language:- Read more:Introduction
Introduction to Classes in C++ 2007-06-15 02:00:00 Classes are the building blocks of Object Oriented Programming in C++ language.
Class gives us the ability to simplify certain types of programs by creating
objects that are programmed to resemble real-world objects in terms of data
and behavior (functions).
Just like identifiers of built-in data types (ex. int, char etc.) are known
as variables similarly identifiers (instances) of class are known as Objects.
Classes in C++ have two parts, data and functions; these are known as data
members and member function respectively. Member functions are usually the means
of accessing and modifying data members.
Anything inside the class can be either private to the class or public to the
program. Classes may have both type of members (private and public) at the same
time.
General form of Class:
class class_name
{
access-specifier:
member…
member…
member…
access-specifier:
member…
member…
member…
}object-list;
Few points to remember:
Access-specifier Read more:Classes
, Introduction
Method of Adding Individual Digits of a Number 2007-06-13 01:01:00 NOTE: The program discussed in this article has no use in practice but
it would definitely help you understand a few things, so please read on…
What this program does is that it takes a number as input (such as 12345) and
outputs the sum of the individual digits, which in this case is 15 (1+2+3+4+5).
For achieving the required result, we need to do two things, first we should
store each of the individual digits in the number and second, we need to add
those numbers, which will give us the required result.
Let us move on to the first stage where we need to separate the digits.
Here are the steps:-
STEP 1: We declare a variable num as integer type and
an array sep again as integer type.
Suppose num=12345
STEP 2: We will be fetching digits from the right (5)
to left (1). For this, we use the modulus (%) operator which divides two
numbers, giving us the remainder.
sep[0]=12345 % 10
Now,
num=12345
sep[0]=5 (last digit has been fetched)
STEP 3: Now num is divided by 10 Read more:Individual
, Number
Introduction to Constructor and Destructor functions of a Class 2007-06-18 00:59:00 Constructor and Destructor functions are Member Functions of a class having
some special property.
Constructor function gets invoked when an object of a class is constructed
(declared) and destructor function gets invoked when the object is destructed
(goes out of scope).
Use of Constructor and Destructor function of a class
Constructor function is used to initialize member variables to pre-defined
values as soon as an object of a class is declared.
Constructor function having parameters is used to initialize the data members
to the values passed values, upon declaration.
Generally, the destructor function is needed only when constructor has
allocated dynamic memory.
Defining Constructor and Destructor functions
The example below illustrates how constructor and destructor functions are
defined:
class myclass
{
private:
int number;
public:
myclass()//constructor
{
number=10;
}
~myclass()//destructor
{
//nothing needed
}
};
A few points Read more:Introduction
Introduction to Function Overloading in C++ 2007-06-17 00:57:00 Let us start this with a question!
All of you know that we cannot have two variables of the same name, but can
we have two Functions having the same name.
The answer is YES, we can have two functions of the same name by a method known
as function overloading and the functions having the same name are known as
overloaded functions.
So, what’s the use of Function Overloading
Function overloading is one of the most powerful features of C++ programming
language. It forms the basis of polymorphism (compile-time polymorphism).
Most of the time you’ll be overloading the constructor function of a
class.
How function overloading is achieved
One thing that might be coming to your mind is, how will the compiler know
when to call which function, if there are more than one function of the same
name.
The answer is, you have to declare functions in such a way that they differ
either in terms of the number of parameters or in terms of the type of parameters
they take.
What that means is, nothing s Read more:Introduction
Unit Conversion Program using Classes 2007-06-16 01:43:00 Welcome back guys, I hope you like my previous article, Introduction to Classes
in C++, in this article we will be further continuing our discussion on classes
in C++. We will not be discussing anything new on the topic though, just a simple
example program to elaborate more on Classes in C++.
In this article, I will show you a program based on classes, which converts
units of length from one to another. The program is simple and I do not think
there is any need for discussing it in detail.
The example program is given below:
//C++ Program
#include<iostream.h>
class length
{
private:
float in_meter, in_cm, in_inch;
public:
void input(float len,int ch);
float output(int ch);
};
//---function definition starts---
void length::input(float len,int ch)
{
switch(ch)
{
case 1://for meter
in_meter=len;
in_cm=in_meter*100;
in_inch=in_cm*2.54;
break;
case 2://for cm
in_cm=len;
in_meter=in_cm/100;
in_inch=in_cm/2. Read more:Conversion
A Multi-Purpose String Class in C++ 2007-06-22 02:27:00 NOTE: Here I present you with a String
Class in C++. We have
pre-defined string class (CString in Microsoft Visual C++) which has similar but
more powerful to the one presented here but using something is one thing and learning
how it works is another. Here I show you how string functions actually work. All
the functions are programmed from the scratch without using any other standard
library function. Look at the program (Class) carefully and try to understand
how each of the function is working.
//-----------------------------
//-----------myClass-----------
//----A String Class in C++----
#include<iostream.h>
#include<stdlib.h>
class myString
{
private:
// these functions are not
// needed outside the class
void allocate(int);
void copy(char *, char *);
public:
char *string;
// member functions
myString();
myString(char *);
int getLength();
int getLength(char *);
void empty();
bool isEmpty();
void putString Read more:Multi
, Purpose
Destructor Functions in Detail 2007-06-20 01:02:00 If you don’t know what destructor functions are, read Introduction to Constructor and Destructor functions of a Class. As the example
programs in this article makes use of the dynamic memory allocation of C++,
so please read Introduction to Dynamic Memory Allocation in C++ , in case you missed it.
When does the destructor function gets invoked
The examples below illustrates when the destructor function gets invoked:
Example 1:
//Example Program in C++
#include<iostream.h>
class myclass
{
public:
~myclass()
{
cout<<"destructed
";
}
};
void main(void)
{
myclass obj;
cout<<"inside main
";
}
OUTPUT:
inside main
destructed
Press any key to continue
As I said in the other article, destructors get invoked when the object of
a class goes out of scope. In this case, the object goes out of scope as the
program terminates. So the destructor gets invoked just before the program’s
termination.
Example 2:
//Example Pr Read more:Detail
, Functions
Introduction to Dynamic Memory Allocation in C++ 2007-06-19 01:29:00 Suppose you are making a C++ program to store a particular number (specified
by the user at runtime) of phone numbers. What will you do? You cannot declare
array of 10 or 20 elements because you don’t know how many numbers the
user will enter. He may want to enter 1, 10 or even 100 phone numbers.
So what will you do?
Actually, you can do two things to achieve this, that are listed below:
You can create a very large int(eger) array (say, of 500 elements) , in
this case whether the user wants to store 1 or 500 phone numbers, the memory
used will always be the same (large!).
You can make use of C++’s dynamic memory allocation to allocate only
the needed amount of memory.
The first choice is a very bad way of programming, nevertheless it works fine,
you should never employ such an inefficient method of programming.
So, you are left with only one choice to use the DynamicMemory
Allocation
of C++ programming language, th Read more:Introduction
Binary Search: A Method of Searching 2007-06-25 05:41:00 Binary Search
method is popular for searching a specific item in an ordered
array (sorted). It can perform the search in minimum possible comparisons, but
it needs the array to be sorted in any order.
Practically, it is used when the data is itself sorted initially or needs to
be sorted for other activities also. This is because you don’t want to
first sort the data and then use binary search, in that case use of linear search
would be practical.
Binary Search Algorithm
Suppose,
The array to be AR[SIZE] having SIZE number of elements.
L is the index number of the lower element. We take it to be 0.
U is the index number of the upper (last) element. It will be (SIZE-1).
ITEM is the data that needs to be searched.
beg, last and mid are variables of type int(eger).
Here is the algorithm:
LET beg = L AND last = U
REPEAT STEPS 3 THROUGH 6 TILL beg<=last
mid = ( (beg+last)/2)
IF AR[mid] = ITEM THEN
ITEM IS AT POSITION mid
BREAK THE LOOP
IF AR[mid] < Read more:Binary
Sorting an Array using Bubble Sort 2007-06-25 05:39:00 In this article we will see how an array can be sorted using Bubble
Sort Technique.
Sorting
, as you know, is the method of arranging the elements of an array in
an order (ascending or descending).
The basic idea behind bubble sort method of sorting is to keep on comparing
adjoining elements of the array from the first until the last and interchanging
them if they are not in proper order. The whole sequence is repeated several
times when the array becomes sorted.
Bubble Sort Algorithm
Suppose,
The array (to be sorted) to be AR[SIZE] having SIZE number of elements.
L is the index number of the lower element. We take it to be 0, since the
whole array has to be sorted.
U is the index number of the upper (last) element. It will be (SIZE-1).
Here is the algorithm of sorting the array using bubble sort
FOR I = L TO U
FOR J = L TO (U-1)
IF AR[J] > AR[JA1] THEN
temp = AR[J]
AR[J] = AR[J+1]
END OF INNER LOOP
END OF OUTER LOOP
Now that you know the algorithm, Read more:Array
Classes & Objects: Dynamic Memory Allocation 2007-06-24 01:19:00 Just as variables of pre-def data type are dynamically allocated, same way
objects of class can also be dynamically allocated. While the method of doing
this is no different but the way members of such objects are accessed is a bit
different. This is why I thought of writing a separate article on it.
Before discussing any further, look at the program below:
// Example Program in C++
#include<iostream.h>
// class
class myclass
{
// by default everything is
// private to the class
int var1, var2;
void add();
public:
int sum;
void input(int,int);
};
// function definitions
void myclass::input(int a, int b)
{
var1=a;
var2=b;
add();
}
void myclass::add()
{
sum=var1+var2;
}
// main function starts
void main(void)
{
myclass obj; // simple object
myclass *pobj; // pointer
// of type 'myclass'
pobj=&obj; // now 'pobj' pointer
// points to the object 'obj' of
// class 'myclass'
Read more:Classes
, Dynamic
, Memory
Features of C++, we haven't discussed... 2007-06-23 01:38:00 In this article, we will discuss about certain features of C++ Programming
Language, which we haven’t discussed so far. All the features are discussed
with the help of example programs so that you could straightaway learn to use
them.
Let us have a look at them one-by-one:
(Things are discussed in the comments wherever necessary)
EXAMPLE 1: Variation of for-loop
// Example Program in C++
#include<stdio.h>
#include<conio.h>
void main(void)
{
char ch;
for(;;)
{
// this loop will run
// infinitely till
// 'q' is pressed
ch=getch();
if (ch=='q' ch=='Q') break;
}
printf("out of loop
");
}
EXAMPLE 2: Variation of for-loop
// Example Program in C++
#include<iostream.h>
void main(void)
{
char str[20]="learn C++";
for(int i=0;str[i];i++)
;// notice that there
// is nothing in the
// body of the loop
cout<<"length of str :"<<i;
cout<<endl;
}
OU
Reference Variables in Detail 2007-06-23 01:35:00 A reference is an alias or alternate name for an object. It is just like having
two variables having the same memory address, if one of them changes the other
will also change.
Actually, a reference is an implicit pointer. Suppose, we have an int(eger)
variable num and its reference refnum, then
both will always have the same value no matter which one gets alerted.
We can have independent references, reference parameters in functions, functions
returning references etc. that are illustrated below with the help of example
programs:-
EXAMPLE 1: Independent Reference to a variable
// Example Program in C++
#include<iostream.h>
void main(void)
{
int num;
// notice the declaration of a reference
// & has nothing to do with the 'address
// of' operator (&)
int &refnum=num;
cout<<"enter value for num: ";
cin>>num;
cout<<"now refnum="<<refnum;
cout<<"
enter value for refnum: ";
cin>>refnum;
cout< Read more:Detail
Algebra of Matrices (2D Arrays) Part II 2007-06-29 04:58:00 As you know from the previous article, matrices are 2D arrays. In the previous
article, we saw how two matrices are added and subtracted. In this article,
we will continue our discussion on algebra of two matrices by discussing how
two matrices are multiplied.
Multiplication of two Matrices
Multiplication of two matrices mat1[a x b] and mat2[p x q] is only valid if
b=p. While there are many algorithms by which two matrices can be multiplied,
here I’ll give you the most simple algorithm. Others are used when efficiency
matters.
Algorithm for Multiplication of two Matrices
Suppose,
Two 2D arrays to be mat1 [p][p] and mat2 [p][p] having same number of rows
and columns.
A third 2D array, mul [p][p] to store the result.
Here is the algorithm:
FOR I = 0 TO (p-1)
FOR J = 0 TO (p-1)
mul [I][J] = 0
FOR K = 0 TO (p-1)
mul [I][J] += (mat1 [I][K] * mat2 [K][J])
END OF INNER LOOP
END OF OUTER LOOP
Below is a example program which illustrates the multiplication of two mat
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