#include<stdio.h>
#include<stdlib.h>
int fact(int arr[], int i)
{
if (i == 0)
return arr[0];
else
return arr[i] + fact(arr, i-1);
}
int main() {
int n;
int arr[100];
printf("输入n的值(n>=1):");
scanf_s("%d", &n);
for (int i = 0; i < n; i++)
arr[i] = i + 1;
printf("1到%d的和为:%d\n", n,fact(arr,n-1));
system("pause");
return 0;
}