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.
#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;
}