Program to solve simultaneous equation using by Guess elimination method

#include<stdio.h>

#include<conio.h>

#include<math.h>

//#include<stdlib.h>

int main()

{

int n,i,j,m,k,p,q;

float e,a[10][10],x[10],temp,max,sum,u;

//clrscr();

printf("enter the number of equations :");

scanf("%d",&n);

printf("\nenter the co-efficients of equations\n");

for(i=1;i<=n;i++)

 for(j=1;j<=(n+1);j++)

  scanf("%f",&a[i][j]);

printf("\nenter the value of prescribed precision :");

scanf("%f",&e);

printf("\nentered co-efficient matrix is\n");

for(i=1;i<=n;i++)

{

 for(j=1;j<=(n+1);j++)

  printf("%.2f\t",a[i][j]);

 printf("\n");

}

    //Lower Triangularisation Steps//

for(k=1;k<=(n-1);k++)

   //Pivotal Condensation Steps//

{

  max=fabs(a[k][k]);

  p=k;

  for(m=(k+1);m<=n;m++)

    if(max < fabs(a[m][k]))

    {

      max=fabs(a[m][k]);

      p=m;

    }

  if(max <= e)

  {

    printf("\nill conditional equation\n");

    return(0);

  }

  if (p!=k)

    for(q=k;q<=(n+1);q++)

    {

      temp=a[p][q];

      a[p][q]=a[k][q];

      a[k][q]=temp;

    }

    //End of Pivoting Steps.

  for(i=(k+1);i<=n;i++)

  {

    u=a[i][k]/a[k][k];

    for(j=k;j<=(n+1);j++)

      a[i][j]=a[i][j]-(u*a[k][j]);

  }

}

  printf("\nLower Triangularised matrix is\n");

  for(i=1;i<=n;i++)

  {

    for(j=1;j<=(n+1);j++)

      printf("%.2f\t",a[i][j]);

    printf("\n");

  }

     //End Lower Triangularisation Steps//

     //Backward Substitution Steps //

  x[n]=a[n][n+1]/a[n][n];

  for(i=(n-1);i>=1;i--)

  {

    sum=0;

    for(j=i+1;j<=n;j++)

      sum=sum+a[i][j]*x[j];

    x[i]=(a[i][j]-sum)/a[i][i];

  }

  printf("\nsolution vector is\n");

  for(i=1;i<=n;i++)

    printf("x[%d]=%.2f\n",i,x[i]);

  getch();

}