1-3+5-7+......-99+101

#include<stdio.h>
main()
{
	int s=0,t=1,i=1,sign=1;
	while(i<=101)
	{
		s=s+t;
		i=i+2;
		sign=-sign;
		t=i/sign;
	}
	printf("%d",s);
}