#include <stdio.h> int fun(int n) { if(n==100) return 100; else return n+fun(n+1); } int main () { printf("1到100的和是%d",fun(1)); } /*#include <stdio.h> int fun(int n) { if(n==1) return 1; else return n+fun(n-1); } int main () { printf("100到1的和是%d",fun(100)); } */