How do I get GCC to work? - c

Question

I am using Vim as my editor and GCC as my compiler, but it’s not working quite right. Let‘s say I am making a basic program to determine if a number is odd or even. Here is my code:
#include <stdio.h>
int main(int argc, char argv[])
{
int i;
printf("Enter a number: ");
scanf("%d\n", &i);
printf("%d\n", i);
if(i % 2 == 0)
{
printf("Your number is even.\n");
}
else if(i % 2 != 0)
{
printf("Your number is odd.\n");
}
else
{
printf("Invalid input.\n");
}
getchar();
return 0;
}
I'm not sure if I am programming this wrong, or gcc is just not a good compiler, or whatever. I am running linux, which I dual boot with windows. Now I press ctrl-d to stop the process, and only then does it print me back my number, and tell if it is odd or even. It isn't just this one, a lot of other programs with similar formats seem to do this to.
~ $ ./test
Enter a number: 45
45 //I press enter, nothing happends. Ctrl-d
Your number is even. //ctrl-d again
~ $
So what I'm asking is, is there a way to program it so that I don't have to quit the program in order for it to work, or is there another compiler that wouldn't have this problem? I am running on Ubuntu 14.04 dual booted with Windows 8.1.

Answer 1

\n in the format for scanf means "read until hit into non-whitespace character and then ignore them". Remove it and make the format for reading "%d".

Answer 2

to get gcc to work from vim,
goto the vim command prompt
shell gcc <and all needed parameters>
Or open another command window
set it to the same directory as the program being edited
gcc <and all needed parameters>
in general, try to make the compile step separate from the link step. I.E. to compile:
gcc -c <mySource.c> -Wall -Wextra -pedantic -std=c99 -o mySource.o
if any header files, other than those in the default 'include' path then add
-I<pathToHeaderFile>
which is often in the same directory so would be:
-I.
then link with:
gcc mySource.o -o mySource
You can add the -ggdb parameter to both lines if you plan on doing any debugging.
to add any library directories then on the link step append
-L<pathToLibrary>
to add any libraries then on the link step append, after any library parameters:
-l<shortLibName>
The initialization file for vim can contain the necessary info to invoke gcc by some keystroke combination, but I'm not totally familiar with the details.