C function call strange error

Question

I'm trying to call a function in main for the different programs (Q2-3 and Q4) but I'm getting an error during compiling. in my main I have prog1 (); [it says "previous implicit declaration of prog1 was here"] then there is a function of the same name at the very end void prog1() { [it says "conflicting types for prog1"] and yes it just says it on a line where the only thing is {

the [] are just what I typed here not what is in my code. If you need more parts of my code let me know. My program is written in C not C++

Answer 1

Because you didn't give a prototype for prog1() .

If it has for example the following signature

char *prog1(void);

and you don't give a prototype but call it from main() , then you define it later with the mentioned signature, the implicitly declared prototype which is int prog1() conflicts with the definition.

Just add a prototype before main() .