# include <stdio.h> long sum(int n) { //用递归实现: if (n == 1) return 1; else return sum(n-1) + n; /* 用for循环实现: long s = 0; int i; for (i=q; i<=n; ++i) s += i; return s; */ } int main(void) { int val; printf("请输入您需要累加的值:"); scanf("%d", &val); printf("累加结果为:%ld ", sum(val)); return 0; }