Suppose that there asked user to input char variable. How to make c++ to recognize entered character as int if it is a digit?

Question

C++

Answer 1

If a user is entering data in the form of a string, then you can use the atoi function to change it to an int.

Format: atoi(const char * str)

Answer 2

Based on the ASCII table you can use this condition:

if (c>='0'&&c<='9')

Answer 3

Also, if you know beforehand that the input is a number, you can use:

int input;
cin >> input;

Answer 4

you you have a chat variable "input" storing entered digit, then to convert it to int you can do this:
int converted = input - '0';