Parsing a string A string is a sequential object that has zero, one or many characters. This lab asks you to ask the user for a string and then count the number of digits in the string.

NOTE: You must do this with a WHILE loop, not a FOR.

How can you tell if a character is a digit? If you have a string variable named str, you. can make a Boolean expression that will be True by doing this: str. isdigit() So if I code: str="spam" then str. isdigit() will be False But if I code: str =. "1984" then str. isdigit() will evaluate to True.

The strings will have digits and non-digits mixed. You must look at each character of the string by itself. You do this by indexing the string. If i is an index variable, then str[i] will give you the character at the i-th position in the string (remembering that it is indexed from zero).

We as humans write math expression in infix notation, e.g. 5 + 2 (the operators are written in-between the operands). in a computer’s language, however, it is preferred to have the operators on the right side of the operands, i.e. 5 2 +. for more complex expressions that include parenthesis and multiple operators, a compiler has to convert the expression into postfix first and then evaluate the resulting postfix.write a program that takes an “infix” expression as input, uses stacks to convert it into postfix expression, and finally evaluates it. it must support the following operations: + - / * ^ % (example infix expression: (7 - 3) / (2 + 2)postfix expression: 7 3 - 2 2 + /result: 1guidelines: 1. you will need to use stacks in three placesa. one for the parenthesis check [char stack]b. one during infix to postfix [char stack]c. one during evaluation [int stack]for a and b above, you can use same array and same push, pop method as both ofthem are char. but for evaluation you have int stack and you might consider to createanother push pop method to handle it. maybe push_int, pop_int, etc. or find otherstrategy to utilize existing push pop method2. you can create a function for obtaining operator priority. that function should take anoperator as input and return its priority as an integer. this function will you a lot andreduce repeated code3. during evaluation you will need to convert char into integer. example for single digit: char c = '5'; int x = c - '0';