c programming language

Applications Programming
1

Can someone enligten me on what below program does?
I understand getchar and putchar.. but what is this program suppose to do?
I try to put printf on it, but it shows nothing..

can someone explain to me what this program is suppose to do?
It is reading something and assigning to c?

so, if I do, ./a.out filename , will it assign entire filename's content into c?

#include <stdio.h>

/* copy input to output; 1st version */

main()
{
int c;

c = getchar\(\);
while \(c != EOF\) \{
   putchar\(c\);
   c = getchar\(\);
        \}

}

2

Hi,
The program basiaclly copies the character entered by the user to the variable c and then rits it to the output.
This goes on until the user enters the EOF character(I am not sure abt the character)

Thanks
Raghuram

3

You would need to do:
./a.out < input.file > output.file
to run it.

4

do it like this
./a.out</etc/apt/source.list

and you will see it.
good luck

5

EOF character

ctrl^D

6

I ran it like that.. and seems to work..

but what are the first character and the number?

ni32 <-- example, what is n and 32 for?

n[root@rleeserver programming_language_c]# cat > yahoo
hi
how are you
[root@rleeserver programming_language_c]# ./file_copy <yahoo
h105
ni32
n 10
n
104
nh111
no119
nw32
n 97
na114
nr101
ne32
n 121
ny111
no117
nu10
n
-1

7

I detected mistake in the source for n

#include <stdio.h>

/* copy input to output; 1st version */

main()
{
int c;

c = getchar\(\);
while \(c != EOF\) \{
   putchar\(c\);
   c = getchar\(\);
   printf\("%d\\n", c\);
 \}

}

so, I took it out.. but still put number....

[root@rleeserver programming_language_c]# ./file_copy <yahoo
h105
ni32
n 10
n
104
nh111
no119
nw32
n 97
na114
nr101
ne32
n 121
ny111
no117
nu10
n
-1

Also, EOF is -1? Is there explanation of EOF anywhere on google?(let me google that too as well now).

8

between below program that spits out 0 for EOF and /usr/include/stdio.h, which has , I am bit confused. I ran below program and I do get 0 for EOF..

can someone please help bit further..

/* End of file character.
Some things throughout the library rely on this being -1. */
#ifndef EOF
# define EOF (-1)
#endif

/* This program prompts for input, and then captures a character

  • from the keyboard. If EOF is signalled (typically through a
  • control-D or control-Z character, though not necessarily),
  • the program prints 0. Otherwise, it prints 1.
    *
  • If your input stream is buffered (and it probably is), then
  • you will need to press the ENTER key before the program will
  • respond.
    */

#include <stdio.h>

int main(void)
{
printf("Press a key. ENTER would be nice :-)\n\n");
printf("The expression getchar() != EOF evaluates to %d\n", getchar() != EOF);
return 0;
}

9

8 bit characters are between 0 and 255. EOF has to be outside that range, hence why getchar and fgetc return an int and not a char. If you read that into a char it will work (a) if char is naturally signed (b) character 255 does not appear in the data stream.