008.数列求和

#include <stdio.h>
main()
{
  int i,j,n;
  long sum=0,temp=0;
  printf("Please input a number to n:\n");
  scanf("%d",&n);
  if(n<1)
  {
    printf("The n must no less than 1!\n");
    return;
  }
  for(i=1;i<=n;i++)
  {
    temp=0;
    for(j=1;j<=i;j++)
      temp+=j;
    sum+=temp;
  }
  printf("The sum of the sequence(%d) is %d\n",n,sum);
  getchar();
  getchar();
}