I can give you one hint that is unrelated to the language -- you will not receive anything on cin until the enter key is hit on the keyboard, so there will be no reaction immediately after the '=' key is pressed (your program will hang until the whole line of text is input). Another thing I can tell you that all your operators are binary operators yet you are reading only one number per operator (which is wrong at least once). Other issues you'll have to solve on your own otherwise you wouldn't learn anything.