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

// number of variables
#define N 100
double f[N+2][N+2];
double r[N+2][N+2];

void gauss_seidel_step(){
    int i, j;
    for(i=1; i<=N; i++){
        for(j=1; j<=N; j++){
            f[i][j] = (1.0/4.0)*(f[i-1][j]+f[i+1][j]+f[i][j-1]+f[i][j+1]-r[i][j]);
        }
    }
}

void gauss_seidel_main(){
    int i;
    for(i=0; i<100; i++){
        gauss_seidel_step();
    }
}

int main(){
    int i, j;
    for(i=0; i<=N+1; i++){
        for(j=0; j<=N+1; j++){
            r[i][j] = 0.0;
            f[i][j] = 0.0;
        }
    }
    r[48][50] = 1.0;
    r[52][50] = -1.0;
    
    gauss_seidel_main();
    
    for(i=1; i<=N; i++){
        for(j=1; j<=N; j++){
            printf("%lf ", f[i][j]);
        }
        printf("\n");
    }
    
    
    return 0;
}