#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int sum(int n)
{
int m;
if(n==1)
m=1 ;
else
m=sum(n-1)+n;
return m;
}
int main()
{
int n;
while(1)
{
printf("請輸入n:");
scanf("%d",&n);
printf("1+2+...+%d=%d\n",n,sum(n));
}
return 0;
}
![](https://img.laitimes.com/img/__Qf2AjLwojIjJCLyojI0JCLiQ3chVEa0V3bT9CX5RXa2Fmcn9CXwczLcVmds92czlGZvwVP9EUTDZ0aRJkSwk0LcxGbpZ2LcBDM08CXlpXazRnbvZ2LcRlMMVDT2EWNvwFdu9mZvwVP9cnT1sGVNVDetp1a1cVY0Z1MjZXUYpVd1kmYr50MZV3YyI2cKJDT29GRjBjUIF2LcRHelR3LcJzLctmch1mclRXY39jN2ADMzADNyIzNyUDM1EDMy8CX0Vmbu4GZzNmLn9Gbi1yZtl2Lc9CX6MHc0RHaiojIsJye.jpg)