A useful macro to simulate a REPL in C++.

repl.cc

#include <iostream>

#define REPL(expr)	std::cout << "> " << #expr << std::endl << (expr) << std::endl

int main()
{
	int a = 1, b = 2;
	REPL(a + b);
	// print out:
	//   > a + b
	//   3
	return 0;
}