SRM Div2-147 250score

CCipher.cpp

#include <string>
using namespace std;

class CCipher
{
public:
	string decode(string cipherText, int shift)
	{
        for (int i = 0; i < cipherText.size(); ++i) {
            if (cipherText[i] - shift < 'A') {
                cipherText[i] = 'Z' + cipherText[i] - shift - 'A' + 1; 
            } else {
                cipherText[i] -= shift; 
            }
        }
		return cipherText;
	}
};