While Loop

Relax. We'll talk through this in plain words — no textbook voice.

while loops keep running their code for as long as the condition stays true. They're handy when you don't know ahead of time how many times something needs to run — like repeatedly asking a user for the correct password, or reading a file until you hit the end.

#include <stdio.h>

int main() {
  int i = 0;

  while (i < 5) {
    printf("%d
", i);
    i++;
  }
  return 0;
}

At first, i is 0. Every time the loop runs, i++ bumps it up by 1. i < 5 is no longer true, the loop stops.

You should see

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Info

There needs to be an update inside the loop that eventually makes the condition false. In this example, that's i++.

Easy traps

If you forget i++, you get an infinite loop and the program never stops.