NQueen.c

#include <stdio.h>
int N;
int board[100][100];
int is_attack(int i,int j) {
    int k,l;
    for(k=0;k<N;k++) {
        if((board[i][k] == 1) || (board[k][j] == 1))
            return 1;
    }
    for(k=0;k<N;k++) {
        for(l=0;l<N;l++) {
            if(((k+l) == (i+j)) || ((k-l) == (i-j))) {
                if(board[k][l] == 1)
                    return 1;
            }
        }
    }
    return 0;
}

int N_queen(int n) {
    int i,j;
    if(n==0)
        return 1;
    for(i=0;i<N;i++) {
        for(j=0;j<N;j++) {
            if((!is_attack(i,j)) && (board[i][j]!=1)) {
                board[i][j] = 1;
                if(N_queen(n-1)==1) {
                    return 1;
                }
                board[i][j] = 0;
            }
        }
    }
    return 0;
}

int main() {
    //taking the value of N
    printf("Enter the value of N for NxN chessboard\n");
    scanf("%d",&N);

    int i,j;
    //setting all elements to 0
    for(i=0;i<N;i++) {
        for(j=0;j<N;j++) {
            board[i][j]=0;
        }
    }
    //calling the function
    N_queen(N);
    //printing the matix
    for(i=0;i<N;i++) {
        for(j=0;j<N;j++) {
            printf("%d",board[i][j]);
            printf("  ");
        }
        printf("\n");
    }

}