Validating user input in C programming language. How to stop users entering characters instead of digits!?

Using the C Programming Language, does anyone know how to validate the users input so they can only enter either int, float or double data types (no char!). Usually if you enter a char when your supposed to enter a digit, the program bombs itself. I need to stop the operator from inputing strings or characters.

Validating user input in C programming language. How to stop users entering characters instead of digits!?
Hi,


A standard practice to handle this scenario is to accept only text input from the user, and then use a function like sscanf to convert it to the required format.


For example:





--- old code--


int n;


printf("Enter a number: ");


scanf("%d", %26amp;n);


----------------


--- new code ---


char user_input[1024];


int n;


printf("Enter a number: ");


scanf("%s", user_input);


sscanf(user_input, "%d", %26amp;n);


-------------------


This will enable you to prevent crashes, as well as print suitable error messages based on user input.
Reply:Here is a programme that prints only numeric datatypes on the screen.





# include %26lt;stdio.h%26gt; //Standard libraty


# include %26lt;ctype.h%26gt; //Header file that will check datatype





main ()





{


char c;





while (getch()!='.')//Exit when . is pressed.





{


c=getch();//Get the character from the keyboard





if (isdigit(c))//Validate data type





{





printf("%c",c);//Print datatype only if it is numeric.





}


}





}

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