How to sort functions in C? “previous implicit declaration of a function was here” error

Question

I\'m sure this has been asked before, but I couldn\'t find anything that would help me. I have a program with functions in C that looks like this

function2(         


        

Answer 1

You need to declare (not define) at least one function before using it.

function2();                 /* declaration */
function1() { function2(); } /* definition */
function2() { function1(); } /* definition */

int main(void) { function1(); return 0; }

Answer 2

This is how C works. We need to declare the function before use. like when you use any variable, you must have declare first then you would have use it.

Declaration:- function1(); function2(); and then put your own code.

Answer 3

Foward declare your functions...

function1();
function2();

function2(){
  function1()
}
function1 (){
  function2()
}

main () {
 function1()
}

Answer 4

Forward declare your functions, but by using prototypes. If you have a lot of them such that you can't handle this, this is the moment to think of your design and to create a .h file with all your prototypes. Use

int function1(void);
int function2(void);

if that was what you meant. int function1() already is different from that in C. Help the compiler such that he can help you.

Answer 5

Try:

function1();
function2();

function2(){
  function1()
}
function1 (){
  function2()
}

main () {
 function1()
}