C Tutorial/ctype.h/islower
islower
Item Value Header file ctype.h Declaration int islower(int ch); Return returns nonzero if ch is a lowercase letter; otherwise zero is returned.
<source lang="cpp">#include <ctype.h>
#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>