如下代码怎样才能连续使用 << 1 << 2 ?
还有 << CR ;

#include <iostream>

class myOutText{
public:
    int &operator << (auto s){
        std::cout << s;
    }

    void CR(){
        putchar('\n');
    }

};

int main(void)
{
    myOutText cout; 
    cout << "string<<";
    cout.CR();            // 怎样实现 cout << CR ; 
    cout << "1<<2<<\n";
    cout << 1 << 2;        // 怎样才能连续输出 12 
        
    return 0;
}

 

解决：

#include <iostream>

class myOutText{
public:
    myOutText &operator << (auto s) {   // 返回自身引用以支持连续操作
        std::cout << s;
        return *this;
    }

    void CR() {
        putchar('\n');
    }
};

int main(void)
{
    myOutText cout; 

    cout << "string<<";
    cout.CR(); 
    cout << "1<<2<<\n";
    cout << 1 << 2 << '\n';
        
    return 0;
}

输出：

 

book@100ask:~/Desktop$ g++ test.cpp 
book@100ask:~/Desktop$ ./a.out 
string<<
1<<2<<
12

 

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