How to test against aplhabet input ?

[moroccanplaya]

i have this to check for numeric inputs, which returns then menu if a number is entered less or grater than 5 but i dont know how to do this with alphabets ? for any alphabet or any other charterer apart from numbers should return the menu

while (select < 1 || select > 5) ;
            return select;
 
 
 

[Banfa]

Look up the functions in ctype.h such as isalpha

[donbock]

Are you asking how to work with character constants, when select is a char?

You could do this

if ((select < '1') || (select > '5'))

but this code assumes that the character codes for the digits 1-5 are contiguous. That is true for ASCII, but it may not be true for other character encodings.

A fully portable solution would be something more like this:

while (1) {
   switch (select) {
      case '1':
      case '2':
      ...
      case '5':
         break;
      default:
         return select;
      }
   ...
   }

The switch could be replaced with an if statement.

[Banfa]

but this code assumes that the character codes for the digits 1-5 are contiguous. That is true for ASCII, but it may not be true for other character encodings.

Actually the C standard requires that character constants for the digits be contiguous or rather that '2' - '1' = 1, '3' - '2' = 1 etc.

It is the letters you have to beware of, the standard makes no requirement on contiguity on the alphabet so 'b' - 'a' does not necessarily equal 1.

[moroccanplaya]

the first one works but for example if i enter 1p it executes 1 and automatically executes p as well because i have when someone enters 1 it lets the user create a file which prompts them to enter the file name they want which would automatically be p. i hope that made sense

the example with the switch does not work at all for me it when a user enters a number it just goes strait to default and returns select

[weaknessforcats]

switch (select) { 
      case '1': 
      case '2': 

A '1' is the ASCII character.
A 1 is the integer 1.
You cannot enter the character for 1. It is the integer you enter.

The loop should be:

switch (select) { 
      case 1: 
      case 2: 
etc...

[donbock]

"... but i dont know how to do this with alphabets ? for any alphabet or any other charterer apart from numbers should return the menu"
How do you want to use non-numeric values?