C Loops

for repeats a known number of times, while repeats while a condition is true, and do...while runs at least once.

ExampleC

#include <stdio.h>

int main(void) {
  for (int i = 1; i <= 3; i++) {
    printf("for %d\n", i);
  }

  int n = 3;
  while (n > 0) {
    printf("while %d\n", n);
    n--;
  }

  int k = 10;
  do {
    printf("do-while runs once: %d\n", k);
  } while (k < 5);

  for (int i = 0; i < 10; i++) {
    if (i == 2) continue;
    if (i == 4) break;
    printf("i=%d\n", i);
  }
  return 0;
}

Output

for 1
for 2
for 3
while 3
while 2
while 1
do-while runs once: 10
i=0
i=1
i=3

Quick check

Which loop always runs its body at least once?

forwhiledo...while

Finish the quick check (and any code exercise) to complete this lesson, or mark it done yourself.

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