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

typedef struct offsets{
    short int horiz;
    short int vert;
}offsets ;
offsets move[8]={{1,-2},{2,-1},{2,1},{1,2},{-1,2},{-2,1},{-2,-1},{-1,-2}};

int length,basic_col=0,basic_row=0,token=0;
void set_basic(){
    int ok=0;
    printf("Please set length side of a square:");
    scanf("%d",&length);
    printf("Please set a beginning:");
    do{
        if(ok) printf("Out of range,please enter again!!!\n");
        scanf("%d",&basic_col);
        scanf("%d",&basic_row);
        ok=1;
    }while(basic_col<0 || basic_col>=length ||basic_row<0||basic_row>=length);
}

int chess[100][100]={0};

void printBoard() {
    int col,row;
    for(row=0;row<length;row++) {
        for(col=0;col<length;col++) {
            printf("%3d ", chess[row][col]);
        }
        puts("");
    }
}

void path(int row,int col,int step){
    int nextcol,nextrow,dir;
    if (step == (length * length )&&!chess[row][col]&& !token++) {
        chess[row][col] = step;
        printf( "FOUND!\n");
        printBoard();
        printf( "=============================\n" );
        chess[row][col] = 0;
    }
    if (token) return;
    if (!chess[row][col]&&step !=25) {
        chess[row][col] = step;
        for(dir=0;dir<8;dir++){
            nextcol = col + move[dir].horiz;
            nextrow = row + move[dir].vert;
            if (nextrow < length && nextrow > -1 &&nextcol < length && nextcol > -1) {
                path(nextrow, nextcol, step + 1);
            }
        }
        chess[row][col] = 0;

    }
}

main(){
    set_basic();
    path(basic_row,basic_col,1);
    system("pause");
    return 0;
}