Thread: Character program

Hi there,
I have to make c program that asks to enter a character and find out is it a number, letter or special character.

Here is what i tried:

Code:

#include <stdio.h>
#include <stdlib.h>

main(void)
{
  char ch,a,z,c;

  printf("Enter a character\n");
  scanf("%c", &ch);

  if (c >= 'a' && c <= 'z'){
    printf("%c is a letter.\n", ch);
  }
  if (c >= '0' && c <= '9'){
    printf("%c is a number.\n", ch);
  }
    switch(ch)
  {
    case '"':
    case '{':
    case '(':
    case ')':
    case '&':
    case '^':
    case '%':
    case '*':
    case '#':
    case '!':

      printf("%c is a special character.\n", ch);
      break;
  }

    return 0;
}

Well for one you should have break; inside of each case.

Do you have a specific question?
And would you be willing to try some specialized functions for this purpose?
isdigit - C++ Reference
isalpha - C++ Reference
ispunct - C++ Reference

No, just this example above the task.

I still dont understand what your question is?

You need to be more specific.

These if loops doesnt work. Is there any other mistakes?

"if()" is a conditional statement, not a loop.

Line 9: You read a character into a variable called 'ch'
Line 11: You use 'c' (not 'ch') in your "if()" statement
Line 14: You use 'c' (not 'ch') in your "if()" statement

Originally Posted by hbranum

Well for one you should have break; inside of each case.

This is not true.

Not every case in a "switch()" statement should have a "break." It depends on how you want it to behave. The OP is exploiting the "fall-through" approach of a "switch()" statement.

Sometimes, you want one thing to happen for several different values.

Here's a quick example (it's poor code, but illustrates the concept):

Code:

char input;
int exit;

printf("Continue?  [Y/N] -> ");
scanf("%c",&input);

switch(input)
{
    case 'Y':
    case 'y':
        exit = 0;
        break;
    case 'N':
    case 'n':
        exit = 1;
        break;
    default:
        break;
}

"exit" will be set to zero if the user enters 'Y' or 'y'.
"exit" will be set to one if the user enters 'N' or 'n'.

I didn't understand whats wrong in line 9, but seems like it works anyway

Code:

#include <stdio.h>
#include <stdlib.h>

main(void)
{
  char ch,a,z,c;

  printf("Enter a character\n");
  scanf("%c", &ch);

  if (ch >= 'a' && ch <= 'z'){
    printf("%c is a letter.\n", ch);
  }
  if (ch >= '0' && ch <= '9'){
    printf("%c is a number.\n", ch);
  }
    switch(ch)
  {
    case '"':
    case '{':
    case '(':
    case ')':
    case '&':
    case '^':
    case '%':
    case '*':
    case '#':
    case '!':

      printf("%c is a special character.\n", ch);
      break;
  }

    return 0;
}

Nothing was wrong with line 9 - I just wanted you to see that the variable you were reading into was not the same variable you were using for comparison.

oh yes,Thank you. So is this code ok now? There is no other option for "special characters"? I have to write one by another in every case " "?

Originally Posted by Solarwin

So is this code ok now?

It appears to be okay. I'm assuming you tested it. I'm also assuming the character variables 'a', 'z', and 'c' are there because you plan on growing this program (they have no use in the program thus far).
Some sticklers might recommend a "default" case in your "switch()" statement for consistency, even if it just executes a "break", but for purposes of this code, it's alright without it.

Originally Posted by Solarwin

There is no other option for "special characters"?

You don't have specifications/instructions to tell you this? There are others you could add ('+' '-' '$' '.' for instance)

Originally Posted by Solarwin

I have to write one by another in every case " "?

I don't understand this question. Can you clarify?

Nope, i wasn't planning on growing this.
I dont have any other instructions.I think i have to add all of C Character Set these special characters. I was wondering if there is any way how to add them without using "switch" and "cases". It is kind of boring to copy and paste all of these characters.

Code:

#include <stdio.h>
#include <stdlib.h>

main(void)
{
  char ch;

  printf("Enter a character: ");
  scanf("%c", &ch);

  if (ch >= 'a' && ch <= 'z'){
    printf("%c is a letter.\n", ch);
  }
  if (ch >= '0' && ch <= '9'){
    printf("%c is a number.\n", ch);
  }
    switch(ch)
  {
    case '"':
    case '{':
    case '(':
    case ')':
    case '&':
    case '^':
    case '%':
    case '*':
    case '#':
    case '!':

      printf("%c is a special character.\n", ch);
      break;
      default:
      break;

  }

Programming is exciting, but it can be tedious at times. Sometimes, you have to accept that. You do have some options, though.

1. Copy and paste them all. Time-consuming, but easy and guaranteed to meet the requirements.

2. Look up the values on the ASCII chart, and do more ">= and <=" comparisons to check case values in bulk. This is somewhat more elegant than the "switch()" implementation you have, but it's not guaranteed to be universal, as character sets may vary on some machines.

3. Use the "ispunct()" function I linked in post #3. This would be the easiest and nicest way to check, since it seems to check for all the characters you need it to for the "special" case. There's a link there to another page that has a table which lists which symbols "ispunct()" is valid for.