C++ How to Implement Menu with Number and Letter Choices [closed] - c++

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I want to use a menu in C++ that has options both in letters and numbers. For example, the output might be:
========================
(1) Do something
(2) Do something
(a) Do something
(b) Do something
========================
Is there a method for testing user input to determine if it is a char or int and handle it accordingly?
If I use:
int choice;
cin >> choice;
And the user inputs a char, of course cin will return an error. I'm looking for a simple method to test user input for a digit or a character and have the program react differently based on that determination.
[UPDATE]
I've found the answer I was looking for. Here's how I did it:
string choice;
cout << "Your choice: ";
cin >> choice;
if( isdigit(choice[0]) )
{
theInt = stoi(wChoice);
// do something with int
}
else if( choice[0] = 'a' )
// do menu option a

Answer 1

You'd better use the method isdigit in the ctype.h to check if character is a decimal digit character, and the method isalpha to check if character is alphabetic.

Answer 2

"For example, there could be options: 1, 2, 3, n, s."
The simplest solution I see is to have a menu selection code like
char choice;
std::cin >> choice;
switch(choice) {
case `1`:
// Do menu option one
break;
case `2`:
// Do menu option two
break;
case `3`:
// Do menu option three
break;
case `n`:
// Do menu option "n"
break;
case `s`:
// Do menu option "s"
break;
}
If you need to handle numeric choices bigger than 9, you simply use a std::string as input field:
std::string choice; // <<<
std::cin >> choice;
in turn a switch statement cannot be used any more and you have to change it to an if/else if/else cascade:
if(choice == "1") {
// Do menu option one
}
else if(choice == "2") {
// Do menu option two
}
// ...
else if(choice == "42") {
// Do menu option fortytwo
}
else if(choice == "n") {
// Do menu option "n"
}
else if(choice == "s") {
// Do menu option "s"
}

Answer 3

For this, you'll need to read in the input as a string, then parse it to see if it's an alphabetic character or if it's a numeric string. Something along the lines of this (warning, I'm mostly a C programmer, so using C-strings instead of real strings):
#define INPUT_SIZE 8
char input[INPUT_SIZE]; // change size as appropriate
cin.getline(input, INPUT_SIZE);
if (cin.good())
if(input[0] >= '0' && input[0] <= '9') {
int value = atoi(input);
} else if(input[0] >= 'a' && input[0] <= 'z') {
char value = input;
}
}
Naturally, values need different names and actual code paths to deal with them, especially as C++ doesn't have a good built-in "either" type that I know of.
Alternatively, just treat everything as a character, assuming all numeric options are a single character, and test as '0' instead of 0.