The for Loop

When you know how many times to repeat, a for loop is the clearest choice. It puts the start, the condition and the step on one line:

#include <iostream>
using namespace std;

int main() {
    for (int i = 1; i <= 5; i++) {
        cout << "Hello number " << i << "\n";
    }
    return 0;
}

Output

Hello number 1
Hello number 2
Hello number 3
Hello number 4
Hello number 5

The three parts inside the brackets, separated by semicolons:

• int i = 1 – start: runs once, before the loop begins.
• i <= 5 – condition: checked before every round. The loop stops when it is false.
• i++ – step: runs after every round.

Tip: Programmers usually call a simple counter i (for index). It's fine to use it.

Counting in different ways

#include <iostream>
using namespace std;

int main() {
    // Count from 0 to 4 (very common in C++)
    for (int i = 0; i < 5; i++) {
        cout << i << " ";
    }
    cout << "\n";

    // Count down
    for (int i = 10; i >= 1; i--) {
        cout << i << " ";
    }
    cout << "Lift off!\n";

    // Count in steps of 5
    for (int i = 0; i <= 25; i += 5) {
        cout << i << " ";
    }
    cout << "\n";
    return 0;
}

Output

0 1 2 3 4 
10 9 8 7 6 5 4 3 2 1 Lift off!
0 5 10 15 20 25 

A times table

#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    for (int i = 1; i <= 5; i++) {
        cout << n << " x " << i << " = " << n * i << "\n";
    }
    return 0;
}

Input (what the user types)

7

Output

7 x 1 = 7
7 x 2 = 14
7 x 3 = 21
7 x 4 = 28
7 x 5 = 35

Remember: A variable created inside the for brackets (like i) only exists inside that loop.