#include <iostream>
#include <string>
/**
* return the last n characters of a string,
* unless n >= length of the input or n <= 0, in which case return ""
*/
std::string lastN(std::string input, int n) {
    int inputSize = input.size();
    return (n > 0 && inputSize > n) ? input.substr(inputSize - n) : "ccc";
}
 
int main() 
{
	std::string stringToCheck = "0111111";
 
    std::string lastN(stringToCheck, 4);
 
    std::cout << "Whole String (stringToCheck): \n";
    std::cout << stringToCheck;
 
    std::cout << "\n\nSubstring (stringToCheck - n Characters \ne.g. if n = 4, indices 0,1,2,3 get removed from the string): \n";
    std::cout << lastN;
 
	return 0;
}

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