嵌入式笔试刷题（第29天）

1. 实现字符串类 String 的构造、析构与赋值函数

class String {
public:
    String(const char* str = NULL) {
        if (str) {
            m_data = new char[strlen(str) + 1];
            strcpy(m_data, str);
        } else {
            m_data = new char[1];
            *m_data = '\0';
        }
    }

    String(const String &other) {
        m_data = new char[strlen(other.m_data) + 1];
        strcpy(m_data, other.m_data);
    }

    ~String() {
        delete[] m_data;
    }

    String& operator=(const String &other) {
        if (this == &other) return *this;
        delete[] m_data;
        m_data = new char[strlen(other.m_data) + 1];
        strcpy(m_data, other.m_data);
        return *this;
    }

private:
    char* m_data;
};

2. 八皇后问题 C 语言实现

#include <stdio.h>
#define N 8

int count = 0;
int board[N];

int isSafe(int row, int