C++ For Loop
When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop:
Syntax
for (statement 1; statement 2; statement 3) {
// code block to be executed
}
Statement 1 is executed (one time) before the execution of the code block.
Statement 2 defines the condition for executing the code block.
Statement 3 is executed (every time) after the code block has been executed.
Print Numbers
The example below will print the numbers 0 to 4:
Example
for (int i = 0; i < 5; i++) {
cout << i << "\n";
}
Example explained
- Statement 1 sets a variable before the loop starts:
int i = 0 - Statement 2 defines the condition for the loop to run:
i < 5. If the condition is true, the loop will start over again, if it is false, the loop will end. - Statement 3 increases a value each time the code block in the loop has been executed:
i++
Print Even Numbers
This example prints even values between 0 and 10:
Example
for (int i = 0; i <= 10; i = i + 2) {
cout << i << "\n";
}
Sum of Numbers
This example calculates the sum of numbers from 1 to 5:
Example
int sum = 0;
for (int i = 1; i <= 5; i++) {
sum = sum + i;
}
cout << "Sum is " << sum;
Countdown
This example prints a countdown from 5 to 1:
Example
for (int i = 5; i > 0; i--) {
cout << i << "\n";
}
