写一个C语言实现的八皇后代码

Sure, here's the C code for solving the eight queens problem:

#include <stdio.h>

#define N 8

int board[N][N];

int is_valid(int row, int col) {
    int i, j;
    for (i = 0; i < col; i++)
        if (board[row][i])
            return 0;
    for (i = row, j = col; i >= 0 && j >= 0; i--, j--)
        if (board[i][j])
            return 0;
    for (i = row, j = col; i < N && j >= 0; i++, j--)
        if (board[i][j])
            return 0;
    return 1;
}

int solve(int col) {
    int i;
    if (col >= N)
        return 1;
    for (i = 0; i < N; i++) {
        if (is_valid(i, col)) {
            board[i][col] = 1;
            if (solve(col + 1))
                return 1;
            board[i][col] = 0;
        }
    }
    return 0;
}

int main() {
    int i, j;
    if (solve(0)) {
        for (i = 0; i < N; i++) {
            for (j = 0; j < N; j++)
                printf("%2d", board[i][j]);
            printf("\n");
        }
    } else {
        printf("No solution found.\n");
    }
    return 0;
}

This program uses recursive backtracking to find a solution to the eight queens problem. The `board` array represents the chess board, where `1` indicates a queen is placed, and `0` indicates an empty square. The `is_valid` function checks whether a queen can be placed in a given row and column, without violating the rules of chess. The `solve` function tries to place queens on the board, one column at a time, until a solution is found or deemed impossible. The `main` function simply calls `solve` and prints the resulting board if a solution is found.