Gauss Seidel Method

 

#include<stdio.h>

#include<stdlib.h>

#include<math.h>

/* Defining function */

#define f1(x,y,z)  (17-y+2*z)/20

#define f2(x,y,z)  (-18-3*x+z)/20

#define f3(x,y,z)  (25-2*x+3*y)/20

/* Main function */

int main()

{

 float x0=0, y0=0, z0=0, x1, y1, z1, e1, e2, e3, e;

 int count=1;

 

 printf("Enter tolerable error:\n");

 scanf("%f", &e);

 printf("\nCount\tx\ty\tz\n");

 do

 {

  /* Calculation */

  x1 = f1(x0,y0,z0);

  y1 = f2(x1,y0,z0);

  z1 = f3(x1,y1,z0);

  printf("%d\t%0.4f\t%0.4f\t%0.4f\n",count, x1,y1,z1);

  /* Error */

  e1 = fabs(x0-x1);

  e2 = fabs(y0-y1);

  e3 = fabs(z0-z1);

  count++;

  /* Set value for next iteration */

  x0 = x1;

  y0 = y1;

  z0 = z1;

 }while(e1>e && e2>e && e3>e);

 printf("\nSolution: x=%0.3f, y=%0.3f and z = %0.3f\n",x1,y1,z1);

 return 0;

}