show me this in C++

Write a program to perform simple arithmetic calculations of the form Value operator value For integer values and the operators +, -, *, and /. The user will input an expression such as: 23*5 and the program will output: 23 *5= 115 Write a program to convert a test score into its equivalent letter grade Use an if-else construct, also a switch construct. We will assume that any score over 100 or less than 0 is an error, we could print a message "score is out of range