Introduction

In this post, we will discuss for loop as it is used often in C++ programs. For loop allows you to execute the action for each iteration in the loop.

Syntax

for(for initialization; for expression ; post expression)

{

// loop statements

}

Loop statements can be a single statement or group of statements nested within curly braces.

Flowchart

Sample program

The following code prompts user to enter a number. It uses a for loop to compute the factorial of the number.

/*************************
* C++ for loop demo
*************************/

#include <iostream>
using namespace std;

int main()
{
 int n;
 int factorial=1;
 cout << "Please enter a number : " ;
 cin >> n;
 // for loop
 for(int i=2; i<=n; i++)
 {
 factorial *= i;
 }
 cout << n << " factorial is = " << factorial << endl;
 return 0;
}

run output: Please enter a number : 5 5 factorial is = 120 Process returned 0 (0x0) execution time : 49.577 s Press any key to continue.

For loop is executed until the expression involving the index variable i is false to exit the loop as shown in the flow chart. Any for statement can be converted into a while loop statement in C++.

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