Randomly change position of letters in a string in c++

I have a program that creates a password with upper letters, lower letters, symbols and numbers in this order, but I want to make a subprogram that changes the order of letters in the string, making it completely random, but with out changing the letters, only the order.

Example: "ORVkgr<>74" -> ">Vr7>kgO4R<" or "Ogk4r7<RV>".