While Loops

While Loops

A while loop repeats code as long as a condition stays true.

The basic form

while (condition) {
    // run again and again while condition is true
}

A real example

int i = 0;

while (i < 5) {
    printf("%d\n", i);
    i++;
}

Output:

0
1
2
3
4

The three parts

• The condition checks before each round.
• The body does the work.
• The update (i++) moves toward stopping.

Endless loop danger

If nothing changes the condition, the loop never stops:

while (1) {   // always true!
    printf("forever");
}

TL;DR

• while (condition) { ... } repeats while true.
• The condition is checked before each run.
• The body must eventually make the condition false.
• Use i++ type updates to count safely.