Undefined reference error to function that is actually defined in C

Question

I wrote this program to build a number diamond. The issue is that when I compile the program, it throws the error

build2.c:(.text+0x5): undefined refe

Answer 1

The function print_pattern is not terminated at proper place but instead at the very end of the file:

void print_pattern(int size){
 ...
... end of the loop
}

... more functions
...
... end of print_pattern
}

This results into defining nested functions instead of global level.

It's generally good habit to indent the blocks, in which case you would realized the mistake very quickly.

Answer 2

You seem to have nested functions; this is (a) a non-standard GCC extension, and (b) I presume the scope of the nested get_input() function is the enclosing function, not the file scope. The solution is to move get_input() to file scope. At the end of print_pattern() add an extra }, and delete the final } at the end of the file.

Also, please format your code - most IDEs these days have options to tidy it up, and with correct indentation you may have seen your problem earlier.

Oh, and as a bonus bug fix, you also have in get_input():

while (cont = 1)

This will always be true - use this instead:

while (cont == 1)