#includeint sum(int n); int main() { int n; printf("请输入一个数:n"); scanf("%d",&n); printf("%d",sum(n)); return 0; } int sum(int n) { if(n==0) { return 0; } else { return n+sum(n-1); } }

#includeint sum(int n); int main() { int n; printf("请输入一个数:n"); scanf("%d",&n); printf("%d",sum(n)); return 0; } int sum(int n) { if(n==0) { return 0; } else { return n+sum(n-1); } }