/*
llvm-gcc -O5 -emit-llvm -c -o pi_llvm.bc pi.c
[anders@macbook Desktop]$ time lli -load=/usr/lib/libm.so pi_llvm.bc 800000000
Pi = 3.1415926511

real    0m22.930s
user    0m22.912s
sys     0m0.010s

(gcc 4.2)
gcc -O3 -mtune=native -o pi_gcc4 pi.c
[anders@macbook Desktop]$ time ./pi_gcc4 800000000
Pi = 3.1415926511

real    0m27.328s
user    0m27.318s
sys     0m0.000s
*/

/*
   Name: Pi Calculator Beta.
   Author: Sayan Chakraborti.
   Description: This program calculates the value of Pi.
   Date: Friday, May 31, 2002.
   Copyright: This program is distributed under the GNU General Public License.
   modified to use first arg on cmd line instead of input
*/

#include<stdio.h>
#include<math.h>

int main(int argc, char *argv[])
{
    double r=0, x=1, y=0, s=0, a=0, p=0;
    //printf("\n\n***************************************************************\n\n");
    //printf("Give radius much much greater than 1\nRadius = ");
    //scanf("%lf",&r);
    sscanf(argv[1], "%lf", &r);
    while(x<=r)
        {
                y=sqrt(r*r- x*x);
                s=s+y;
                x=x+1;
        }
    a=(s*4);
    p=a/(r*r);
    printf("Pi = %1.10lf\n",p);
    //printf("\n\n***************************************************************\n\n");
    // getchar();
    return 0;
}