C/Data Type/Char Validation

Check a char: is it a alphanumeric char

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getchar();
   if(ch==".") 
       break;
   if(isalnum(ch)) printf("%c is alphanumeric\n", ch);
 }
 return 0;

}

      </source>

Check a char: is it a control letter

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getchar();
   if(ch==".") 
       break;
   if(iscntrl(ch))
     printf("%c is a control character\n", ch);
 }
 return 0;

}

      </source>

Check a char: is it a letter

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getchar();
   if(ch==".") 
       break;
   if(isalpha(ch)) 
       printf("%c is a letter\n", ch);
 }
 return 0;

}

      </source>

Is a char alphanumeric

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getc(stdin);
   if(ch == ".") break;
   if(isalnum(ch)) printf("%c is alphanumeric\n", ch);
 }
 return 0;

}

      </source>

Is a char punctuation

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getchar();
   if(ispunct(ch)) printf("%c is punctuation\n", ch);
   if(ch == ".") break;
 }
 return 0;

}

      </source>

Is char a control char

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
  ch = getchar( );
  if(ch == ".") break;
  if(iscntrl(ch)) printf("%c is a control char\n", ch);
 }
 return 0;

}

      </source>

Is char a letter

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
 ch = getchar();
 if(ch == ".") break;
 if(isalpha(ch)) printf("%c is a letter\n", ch);
 }
 return 0;

}

      </source>

Is it a digit

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getchar();
   if(ch == ".") break;
   if(isdigit(ch)) printf("%c is a digit\n", ch);
 }
 return 0;

}

      </source>

is it a hexadecimal digit

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getchar();
   if(ch == ".") break;
   if(isxdigit(ch)) printf("%c is hexadecimal digit\n", ch);
 }
 return 0;

}

      </source>

Is it a lowercase char

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getchar();
   if(ch == ".") break;
   if(islower(ch)) printf("%c is lowercase\n", ch);
 }
 return 0;

}

      </source>

Is it a space char

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
 ch = getchar();
 if(isspace(ch)) printf("%c is white space\n", ch);
 if(ch == ".") break;
 }
 return 0;

}

      </source>

Is it a uppercase char

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getchar();
   if(ch == ".") break;
   if(isupper(ch)) printf("%c is uppercase\n", ch);
 }
 return 0;

}

      </source>

Is it printable

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getchar();
   if(isprint(ch)) printf("%c is printable\n",ch);
   if(ch == ".") break;
 }
 return 0;

}

      </source>

Is it printable: isgraph

<source lang="cpp">

1. include <ctype.h>
2. include <stdio.h>

int main(void) {

 char ch;
 for(;;) {
   ch = getchar();
   if(isgraph(ch)) printf("%c is printable\n", ch);
   if(ch == ".") break;
 }
 return 0;

}

      </source>