Examples of for Loop in C++
Example 1
The below example demonstrates the use of a for loop in a C++ program.
C++
// C++ program to illustrate for loop to print numbers from // 1 to n #include <iostream> using namespace std; int main() { // initializing n (value upto which you want to print // numbers int n = 5; int i; // initialization of loop variable for (i = 1; i <= n; i++) { cout << i << " "; } return 0; } |
1 2 3 4 5
Explanation
The above program uses a for loop to print numbers from 1 to n (here n=5). The loop variable i iterates from 1 to n and in each iteration condition is checked (is i<=n i.e i<=5 ), if true then it prints the value of i followed by a space and increment i. When the condition is false loop terminates.
Example 2
Example to demonstrate the use of a for loop in a C++ program for printing numbers from n to 1 (i.e. reverse).
C++
// C++ program to illustrate for loop to print numbers from // n to 1 (reverse counting). #include <iostream> using namespace std; int main() { // initializing n (value upto which you want to print // numbers int n = 5; int i; // initialization of loop variable for (i = n; i >= 1; i--) { cout << i << " "; } return 0; } |
5 4 3 2 1
Explanation
The above program uses a for loop to print numbers from n to 1 (here n=5) the loop variable i iterates from n to 1 and in each iteration condition is checked (is i>=1) if true then it prints the value of i followed by a space and decrement i. When the condition is false loop terminates.
So we can conclude that no matter what the updation is, as long as the condition is satisfied, for loop will keep executing.
Note: Scope of the loop variables that are declared in the initialization section is limited to the for loop block.
Example 3
The program demonstrates the use of a loop with different kinds of updation.
C++
// C++ program to illustrate the use of differnt loop // updation #include <iostream> #include <string> using namespace std; // driver code int main() { // for loop with different kind of initialization for (int i = 32; i > 0; i = i / 2) { cout << "Geeks" << endl; } return 0; } |
Geeks Geeks Geeks Geeks Geeks Geeks
for Loop in C++
In C++, for loop is an entry-controlled loop that is used to execute a block of code repeatedly for the specified range of values. Basically, for loop allows you to repeat a set of instructions for a specific number of iterations.
for loop is generally preferred over while and do-while loops in case the number of iterations is known beforehand.