诡异的程序

#include < iostream.h >
#include < math.h >

void main()
... {
intsign=1,
doubles=0,x=1;
intk=1;
while(fabs(x)>1e-8)
...{
s+=x;
k+=2;
sign=(-1)*sign;
x=sign/double(k);
}
s=s*4;

cout<<s<<endl;
}
// 想用π/4=1-1/3+1/5-1/7......求π，但结果总是4