第一题

//第一题

include<stdio.h>

int main()
{
int i, j, sum, all;
all = 0;
for (i = 1; i <= 50; i++)
{
sum = 0;
for (j = 1; j <= i; j++)
{
sum += j;
} //计算1加到i的和
all += sum; //计算50个sum的和
}
printf("all = %d", all);
return 0;
}