1、計算1到n之間的所有整數的和。
#include <stdio.h>
int sum(int n) { int i; int sum = 0; for (i = 1; i <= n; i++) { sum += i; } return sum; } int main(void) { int x; puts("please input an integer."); printf("x = "); scanf("%d", &x); printf("the sum = %d\n", sum(x)); return 0; }
↓
#include <stdio.h>
int sum(int n) { int sum = 0; while (n > 0) { sum += n; n--; } return sum; } int main(void) { int x; puts("please input an integers."); printf("x = "); scanf("%d", &x); printf("the sum = %d\n", sum(x)); return 0; }