C Tutorial/ctype.h/isalpha
isalpha
Item Value Header file ctype.h Declaration int isalpha(int ch); Return returns nonzero if ch is a letter or zero if not.
<source lang="cpp">#include <ctype.h>
#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>