static long num_steps = 100000;
double step;
void main ()
{ 		int i; double x, pi, sum = 0.0;
		step = 1.0/(double) num_steps;
		for (i=0;i< num_steps; i++){
			x = (i+0.5)*step;
			sum = sum + 4.0/(1.0+x*x);
		}
		pi = step * sum;
}