Can't seem to find an EOF character? - c

Question

I have:
#include <stdio.h>
/* Copy input to output; 2nd version. */
main(void)
{
int c;
while ((c = getchar()) != EOF)
putchar(c);
return 0;
}
I want to terminate the while loop by entering an end-of-line character.
I Have Tried Inputing:
"\t"
"\0"
%d
%f
%c
%x
%n
EOF
"EOF"
\nEOF
int
float
char
long
long long
array
1 => 10
all letters
all symbols on keyboard
.
.
.
Question: What is the magical EOF character that I'm looking for?
*I am Sorry if this is a really easy question for you,but please be nice I'm only a beginner trying to learn something.

Answer 1

On Windows, Ctrl+Z;
on Linux, Ctrl+D.

Answer 2

There is NO EOF character. "EOF" is a logical condition that represents "end of file" has been met.
On Linux machine, you can "signal" the standard input EOF condition by pressing Ctrl+D in the beginning of the line.
Windows systems reserve a character Ctrl+Z, which is 0x1A in hex, to indicate this "end of file" condition. You can input this character by pressing Ctrl+Z. It is still not a real EOF character though. Rather, it is a convention in Windows.

Answer 3

Here ya go #Andy. You just used an int by accident instead of char c.
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
char c;
while ((c = getchar()) != '\t') // while input != tab, remember to use single
putchar(c); // quotes for characters '\n' etc.
system("pause");
return 0;
}
If you are curious about the signals in UNIX/LINUX system this code might help, wrote it for one of my OS labs. Essentially, the program keep asking for a user input. However, when you try to quit during in the beginning with ctrl+z or ctrl+c it doesn't allow you to because the signal gets ignored by the parent and gets handled by the signal handlers for the child process. Note, the parent is sleeping in the beginning, but when it wakes up it kills the child process and ends the program.
#include <stdio.h>
#include <signal.h>
#include <malloc.h>
#include <sys/types.h>
#include <sys/wait.h>
#define maxLength 1024
//****************************************
// Signal Handlers For Child Process
//****************************************
void ctrlchandler(){
signal(SIGINT, SIG_IGN); //Ignore ctrl-c
write(1, "Don't even think about it!", 26);
}
void ctrlzhandler(){
signal(SIGTSTP, SIG_IGN); //Ignore ctrl-z
write(1, "Nice Try.", 9);
}
//****************************************
// Main Program
//****************************************
int main(int argc, char* argv[]){
pid_t pid;
int status;
//Dynamically allocate char array for input line
char *inputLine = (char*)malloc(maxLength*sizeof(char));
//Ignore Ctrl-z and Ctrl-c
signal(SIGINT, SIG_IGN);
signal(SIGTSTP, SIG_IGN);
//Fork Process
if((pid = fork())<0){
//If fork fails
printf("Fork Child Process Faild.\n");
}
//Parent Process
else if(pid != 0){
printf("Parent: My child %d has been spawned.\n",pid);
printf("My pid is %d\n",getpid());
sleep(30);
kill(pid, SIGKILL);
if(waitpid(pid, &status, WUNTRACED))
printf("Child %d has terminated abnormally.\n",pid);
}
//Child Process
else{
sleep(1); //Wait for parent to output first
while(1){
signal(SIGTSTP, ctrlzhandler);
signal(SIGINT, ctrlchandler);
printf("Enter Input:");
fgets(inputLine, maxLength, stdin);
}
}
//Free allocated char array
free(inputLine);
return 0;
}

Answer 4

main()
{
printf ("%d=%x sizeof=%d\n", EOF, EOF, sizeof(EOF));
}
The output is:
-1=ffffffff sizeof=4
EOF is not a char, it is an int
if you type the Control sequence signifying end of file - it will be translated to an int whose value is -1