I am new to linux and I am trying to compile a simple C programme using gcc as a test.After using the vi editor to create the file and converting it using the gcc to an .c extension, when I give the gcc -o test test.c command these are the error messages that i get:
test.c: In function ‘main’:
test.c:3: warning: incompatible implicit declaration of built-in function ‘printf’
test.c:5: warning: incompatible implicit declaration of built-in function ‘scanf’

can someone please clear the doubt and guide as to how avoid this problem since i have to use gcc extensively from here on?

Can you post your code please? Perhaps the problem is that you've not included the relevant header file. You need stdio.h for both printf() and scanf(), i.e. you need a "#include <stdio.h>" at the top of your file. stdio.h contains the definitions for the functions printf() and scanf() (amongst others).

thanks nylex.
the code is as follows
main ()
{ int i , n;
printf("programme to print even numbers in given range");
printf("enter the upper limit: ");
scanf("%d",&n);
printf("\n\n");
for(i = 2; i<=n; i = i+2)
{ printf("\n%d\n",i);
}
}

will try it using the stdio.h header.

Moved: This thread is more suitable in Programming and has been moved accordingly to help your thread/question get the exposure it deserves.

That will fix it. Also, main() should be returning int.

Edit: also, please place your code within code tags in future, to preserve indentation. It just makes it easier to read, really.