/* PI 's  value - Program to find value of pi using the series :  pi^2 / 6  =  1/1^2 + 1/2^2 +.....  + 1/1000^2 */

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

void main()
{
    float  s=0, pi, i ;
    clrscr() ;
    for(i=1 ; i<=1000 ; i++)
        s=s+1/(i*i) ;  /* Parentheses compulsory */
    pi=sqrt(s*6) ;
    printf("The value of pi is %f", pi) ;
    getch() ;
}


/*
Output :

The value of pi is 3.140638
*/