[OOP]重载类型转换操作符

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

class Fraction
{
public:
    Fraction(): num(1), den(1)
    {
    }
    Fraction(int n, int d) : num(n), den(d)
    {
    }

    // 类型转换操作符
    operator double()
    {
        return (double)num/den;
    }

public:
    int num;
    int den;
};


int main()
{
    Fraction fa(4,5);
    double value = (double) fa;
    printf("%f \n", value);

    return 0;
}

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

class Text
{
public:
    Text(const char* str)
    {
        // 申请一块内存, 保存此字符串
        m_size = strlen(str) + 1;
        m_buf = new char[m_size];
        strcpy(m_buf, str);		
    }
    ~Text()
    {
        // 释放此字符串
        delete [] m_buf;
    }

    // 类型转换操作符
    operator const char* ()
    {
        return m_buf;
    }

private:
    int m_size;
    char* m_buf;
};

int main()
{
    Text t1("hello world");
    
    const char* txt = (const char*) t1;
    printf("text: %s \n", txt);
    return 0;
}