#include <stdio.h>

int main()
{
    int c;
    while ((c = getchar()) != EOF){
        putchar(c);

    }
}

hello world
hello world

#include <stdio.h>

int main()
{
    int c,b;
    /* printf(EOF); Segmentation fault (Core dumped) */
    while (b = ((c = getchar()) != EOF)){
        printf("Bool: %dn", b);
        putchar(c);

    }
}

hello world
Bool: 1
h
Bool: 1
e
Bool: 1
l
Bool: 1
l
Bool: 1
o
Bool: 1

Bool: 1
w
Bool: 1
o
Bool: 1
r
Bool: 1
l
Bool: 1
d
Bool: 1