Gioco del 15

#include <stdio.h>
#include <stdlib.h>

void show_array(int (*)[4]);
void move_tile(int (*)[4], char);
int check_win(int (*)[4]);

main(){
    char key;
    int array[4][4]={
        {1,   2,   3,   4},
        {5,   6,   7,  8},
        {9,   10,  11,  12},
        {13,  14,   16,  15}
    };
    do{
        show_array(array);
        key=getchar();
        move_tile(array, key);
        while ((key = getchar()) != '\n' && key != EOF) { } /* clear stdin buffer */
    }while((check_win(array))==0);
    puts("You won");
    return 0;
}

void show_array(int (*arrayPtr)[4]){
    int i, j;
    system("clear");
    puts("Use wasd to play");
    for(i=0;i<4;i++){
        for(j=0;j<4;j++)
            if(arrayPtr[i][j]!=16)
                printf("%d\t", arrayPtr[i][j]);
            else
                printf("\t");
        puts("");
    }
}

void move_tile(int (*arrayPtr)[4], char c){
    void get_current_pos(int (*)[4], int *, int *);
    int i, j;
    get_current_pos(arrayPtr, &i, &j);
    switch(c){
        case 'w':
            if(i<3){
                arrayPtr[i][j]^=arrayPtr[i+1][j]^=arrayPtr[i][j]^=arrayPtr[i+1][j]; /* fast and hot swap */
            }
            else{
                puts("Illegal operation: press enter to continue");
                getchar();
            }
            break;
        case 'd':
            if(j>0){
                arrayPtr[i][j]^=arrayPtr[i][j-1]^=arrayPtr[i][j]^=arrayPtr[i][j-1]; /* fast and hot swap */
            }
            else{
                puts("Illegal operation: press enter to continue");
                getchar();
            }
            break;
        case 's':
            if(i>0){
                arrayPtr[i][j]^=arrayPtr[i-1][j]^=arrayPtr[i][j]^=arrayPtr[i-1][j]; /* fast and hot swap */
            }
            else{
                puts("Illegal operation: press enter to continue");
                getchar();
            }
            break;
        case 'a':
            if(j<3){
                arrayPtr[i][j]^=arrayPtr[i][j+1]^=arrayPtr[i][j]^=arrayPtr[i][j+1]; /* fast and hot swap */
            }
            else{
                puts("Illegal operation: press enter to continue");
                getchar();
            }
            break;
        default:
            puts("Wrong key: press enter to continue");
            getchar();
    }
}

int check_win(int (*arrayPtr)[4]){
    int flag=1;
    int i, j;
    for(i=0;i<4;i++)
        for(j=0;j<4;j++)
            (arrayPtr[i][j]==(4*i+j+1))?:(flag=0);
    return flag;
}

void get_current_pos(int (*arrayPtr)[4], int * m, int * n){
    int i, j;
    for(i=0;i<4;i++)
        for(j=0;j<4;j++)
            if(arrayPtr[i][j]==16){
                *m=i;
                *n=j;
            }
}