課程

/后端開發(fā)

/C

/C語(yǔ)言入門

#include?<stdio.h>
int?main()
{
????
????int?sum=0;
????int?i=1;
????int?flag=1;
????for(i=1;i<=100;i++);
????{
????????sum+=i*flag;
????	flag*=-1;
????}
????printf("sum=%d\n",sum);
????return?0;
}