Why is this simple c programming reading an extra newline from stdin?-CodePudding

I'm following the second edition of the K&R C book and got to exersize 1.5.1. I was playing around with their provided code and wrote the following:

#include <stdio.h>

int main() {
    int c;
    while (1) {
        printf(">>> ");
        c = getchar();
        if (c == EOF) {
            printf("\nGoodbye\n");
            return 0;
        }
        putchar(c);
        printf("\nhex: %x, dec: %d\n", c, c);
    }
}

Saved as main.c and compile with gcc main.c -o main. Here's an example output when I successively input 1, 12, then ^D:

./main
>>> 1
1
hex: 31, dec: 49
>>> 

hex: a, dec: 10
>>> 12
1
hex: 31, dec: 49
>>> 2
hex: 32, dec: 50
>>> 

hex: a, dec: 10
>>> 
Goodbye

Notice the empty >>> lines. These indicate to me that getchar is picking up on the linefeeds I provide when I press the enter key. However, if I simply remove the last printf (line 13), recompile, and rerun with the same input, this is the output I get:

./main
>>> 1
1>>> 
>>> 12
1>>> 2>>> 
>>> 
Goodbye

As you can see, the code is no longer acting as though it received empty linefeeds as input. Why does removing the last printf cause this?

CodePudding user response：

Upon further inspection, the program is acting as it should be. Thank you @KamilCuk, I'm not entirely sure how I missed that.

CodePudding user response：

./main
>>> 
1>>>                << empty line
>>> 12
1>>> 2>>>           << empty line
>>> 
Goodbye