Write a C++ program that has asks the user to enter a string-input. If the string matches the password stored in the program, then print a suitable welcome message, otherwise allow the user to re-enter the correct password. The user has at most 3 chances to enter the correct password, else a suitable error message is displayed and the program is terminated.
More seems like a challenge or something?
At least to achieve this you really only need very basic knowledge of C++. A friend of mine was able to do almost the same with no programming knowledge of any kind, just using his intuition and the one hint about std::cin, std::cout and std::string to exist, but not how to use them.