Question

用c语言编写计算1+（1+2）+（1+2+3）+（1+2+3+4）+……+（1+2+3+……+n）的值

Answer 1

#include <stdio.h>
long long sum1(long n){
    long long count,sum1=0;
    for(count=1;count<=n;count++)
    {
        sum1+=count;
    }
    return sum1;
        }

long long sum2(long n){
    long long count,sum2=0;
    for(count=1;count<=n;count++)
    {
        sum2+=sum1(count);
    }
    return sum2;
        }

int main(){
        printf("设定n的值:");
        long long n;
        scanf("%lld",&n);
        long long result=sum2(n);
        printf("结果为%lld\n",result);
        return 0;
        }

Answer 2

#include <stdio.h>

int result(int n);

int main(void)
{
int n,i,sum = 0;
printf("please input n: ");
scanf("%d",&n);
sum = result(n);
printf("value is %d\n",sum);
return 0;
}

int result(int n)
{
int sum = 0,i;
for(i = 1;i <= n;i++)
sum += i;
if(n > 1)
sum += result(n - 1);
return sum;
}