Материал из C\C++ эксперт
int isalnum(int ch)
//Declaration: int isalnum(int ch);
//Return: returns nonzero if its argument is either a letter of the alphabet or a digit.
returns zero if the character is not alphanumeric.
#include <ctype.h>
#include <stdio.h>
int main(void)
{
char ch;
printf(". to exit:");
for(;;) {
ch = getc(stdin);
if(ch == ".")
break;
if(isalnum(ch))
printf("%c is alphanumeric\n", ch);
}
return 0;
}
/*
2 is alphanumeric
1 is alphanumeric
1
1 is alphanumeric
2
2 is alphanumeric
12
1 is alphanumeric
2 is alphanumeric
1
1 is alphanumeric
1
1 is alphanumeric
1
1 is alphanumeric
!
~
.
*/
