In do-while loop, condition is always tested after the the execution of the iteration and if condition fails, loop terminates. Therefore, do-while loop executes at least one iteration before termination if condition fails in first iteration! For example:
#include <stdio.h> int main(void) { int counter = 0; do { /* loop executes just once printing the value 0 */ printf("counter is %dn", counter); } while(counter++ != 0); return 0; }
In while loop, condition is checked before execution of each iteration and as condition fails, loop terminates. For example:
#include <stdio.h> int main(void) { int counter = 0; /* loop terminates in the beginning of first iteration */ while (counter++ != 0) printf("counter is %dn", counter); /* here counter val is printed as 1 */ printf("counter is %dn", counter); return 0; }
