CODEWITHSUNDEEP
c++stream
Albert
Albert

Reputation: 1123

Detect end of line before next one

I don't know how to "buffer" a line of input (and perform some operations on that line, e.g. insert a newline at the end) before the next one in the following code:

#include <iostream>

class Test {
  public:
    template<class T>
    Test& operator<< (T&& anything) {
        std::cout << anything;
        return *this;
    }

};

int main() {
    Test myobj;

    myobj << "hello" << "this is cool";
    // How to insert a newline here?        
    myobj << "but" << "this is NOT cool";
}

I'd like to be able to detect when the line

myobj << "hello" << "this is cool";

has completed before the next one is executed.

Upvotes: 1

Views: 58

Answers (2)

David G
David G

Reputation: 96800

You can detect it in its destructor. Create a log() helper function that returns a temporary. At the end of the full expression its destructor will run:

class Test {
public:
    template<class T>
    Test& operator<< (T&& anything) {...}

    ~Test() { std::cout << std::endl; }
};

Test log() { return Test(); }
// ...
log() << "hello" << "this is cool";   // destructor inserts a newline here
log() << "but" << "this is NOT cool"; // here too

Upvotes: 0

Steephen
Steephen

Reputation: 15824

`"\n"`

do it for you as shown below:

int main() {
    Test myobj;

    myobj<< "hello" << "this is cool<<"\n"";
    // How to insert a newline here?        
   myobj << "but" << "this is NOT cool";
}

Or otherwise you use std::endl as follows

myobj << "hello" << "this is cool<<std::endl;

Upvotes: 1

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