C

c check if character is a digit

char ch = '1';
if(isdigit(ch))
  printf("numeric");     
else
    printf("alphabet" );
 // output: numeric
CCopy

c check if character is a digit or alphabet

char ch = '/';
 if(isalnum(ch))
   printf("numeric or ap=lphabet");     
 else
     printf("other symbol" );
 //output: other symbol 
CCopy