CS256 - Principles of Structured Design Fall 2021

Displaying ./code/cs256su21code/jun02/break.c

/**
 * This program will read integers from standard input and accumulate a sum of all
 * positive non-negative values.  The `sum = sum + n` statement will be skipped
 * when n is <= 0 because the continue will move execution back to the
 * test-expression of the while loop immediately.
 */

//this is the same program as continue.c but we are also making use of a break statement.

#include <stdio.h>

int main()
{
	int sum = 0, n;

	printf("-- Enter some numbers (one number per line) -- \n");
	printf("-- When finished, type any non-number and hit enter to get the sum of all the numbers--\n");

	/*

		below, we have a while(1), which denotes an infinite loop

		if you are writing a while(1), you need something inside the loop that can cause it to break
		otherwise it will never stop. 

		here, if scanf returns something other than 1 (in this case, reads something other than an 
		integer), the while loop will break.

	*/


	while(1) { //an infinite loop that will only terminate if scanf returns 0.
  		if(scanf("%d", &n) != 1) break;
  		// Note how the test condition is reversed (!= vs ==) since we only want to exit the loop
  		// when the scanf fails to read one integer.
  		if(n <= 0) continue;
  		sum = sum + n;
	}

	printf("sum = %d\n", sum);

	return 0;

}