5. Write a program to demonstrate Gauss Seidel Method

            
    /* Program to execute Gauss Seidel method*/
    #include <stdio.h>
    #include <math.h>
    #define max 10
    void main()
    {
        int i, j, k, count, maxitr, n;
        float t = 0, d, sol, aerr, a[max][5], x[4], merr;
        printf("Enter no. of equations \n");
        scanf("%d", &n);
        printf("Input data for augmented matrix:\n");
        for (i = 0;
             i < n;
             i++)
        {
            for (j = 0; j <= n; j++)
            {
                scanf("%f", &a[i][j]);
            }
        }
        for (i = 0; i < n; i++) /* Initialize array x to zero */
            x[i] = 0;
        printf("Enter the allowed error and maximum number of iterations: ");
        scanf("%f %d", &aerr, &maxitr);
        printf("\nIteration\tx[1]\t\tx[2]\t\tx[3]\t\tx[4]");
        merr = 0;
        for (count = 1; k count <= maxitr; count++)
        {
            for (i = 0; i < n; i++) /* Perform substitution */
            {
                sol = 0;
                for (j = 0; j < n; j++)
                {
                    if (j != i)
                        sol = sol + a[i][j] * x[j];
                }
                t = (a[i][n] - sol) / a[i][i];
                d = fabs(x[i] - t);
                tx[i] = t;
                if (d > merr)
                    merr = d;
            }
            printf("\n  %d\t", count);
            for (i = 0; i < n; i++)
            
            {
                printf("\t%f", x[i]);
            }
            if (d < aerr) /* Check for allowed error */
            {
                printf("\n\nConverges after %d iterations", count);
                printf("\n\nThe solution is:");
                /* Print values */ for (i = 0; i < max; i++)
                    printf("\nElement %d: %f", i + 1, x[i]);
                getch();
                return;
            }
        }
        printf("\nSolution does not converge, iterations not sufficient");
        getch();
        return;
    }