Gauss Elimination method (in C)

/*Gauss-Elimination Method for solving Simultaneous equations*/

#include<math.h>

#include<stdio.h>

void main()

{

       unsigned int n,i,r,j,k;

       float a[30][30],x[30],m,s,t;

       printf("****Gauss elimination Method****\n\n\n");

       printf("Enter number of equation:\n");

       scanf("%d",&n);

       printf("Enter the Augmented matrix :\n\n");

       for(i=1;i<=n;i++)

              for(j=1;j<=n+1;j++)

              {

                     scanf("%f",&a[i][j]);

              }

        for(k=1;k<n;k++)

     {

       m=abs(a[k][k]);

       r=k;

       for(i=k+1;i<=n;i++)

       {

        if(abs(a[i][k])>m)

          {

           m=abs(a[i][k]);

           r=i;

          }

       }

       for(j=1;j<=n+1;j++)

       {

        t=a[r][j];

        a[r][j]=a[k][j];

        a[k][j]=t;

        }

        for(i=k+1;i<=n;i++)

        {

           t=a[i][k]/a[k][k];

           for(j=1;j<=n+1;j++)

           a[i][j]=a[i][j]-a[k][j]*t;

        }              

    }

     for(i=n;i>=1;i--)

     {

      s=a[i][n+1];

      for(k=1;k<=n-i;k++)

      s=s-a[i][i+k]*x[i+k];

      x[i]=s/a[i][i];

      printf("\nthe %d th solution is x%d = %f",i,i,x[i]);

     }

     getch();

}

Results: (Gauss Elimination method)

****Gauss elimination Method****

Enter number of equation:

3

Enter the Augmented matrix :

2 1 1 5

3 5 2 15

2 1 4 8

the 3 th solution is x3 = 1.000000

the 2 th solution is x2 = 2.000000

the 1 th solution is x1 = 1.000000

NOTE: Compiler used Visual C++ express 2010