# Exercise 0-8

Is this a valid program? why or why not?

#include <iostream>
int main{}
{
// This is a comment that extends over several lines
// by using // at the beginning of each line instead of using /*
// or */ / to delimit comments.
std::cout << "Does this work?" << std::endl;
return 0;
}


# Solution

Yes. This is a valid C++ Program.

Line comment starts the comment by beginning the line with the //. Whatever follows is a comment, as long as within the same line. The

Once a new line is created, the // is required at the beginning to start another comment.

You can also use the line comment in the middle of a line (so the first part of the line is not a comment, and the second part is a comment). It looks something like this:

std::cout << "Hello World!" << std::endl;  // this is a comment


What I sometimes do is to try out writing the code in an IDE like Code::Block. The auto syntax highlighting within the IDE should give us hints whether the parts in the code are comment or not, indicated by the different colour highlighting. (I would not rely 100% on this though. But it is a good and quick guide I’ve found).

# Reference

Koenig, Andrew & Moo, Barbara E., Accelerated C++, Addison-Wesley, 2000