C programming help!

[ykgoh]

Below is my code that just done halfway, I have issue calling out function_1, it just work within the void main part. Can anyone help to t/s ?thx alot in advance!!

Compile and link no problem/error reported? That's strange.

 

[davidktw]

Compile and link no problem/error reported? That's strange.

If you are referring to the function name, that is fine.

just like you put a expression "10;", it's fine in C

function name is a pointer to the function so statement expression like

function_1; only generate warning since it is unused. It is not an error.

But other parts of the codes might generate warnings depending on the leniency of the compiler.

To: TS

However there should be an error on forward declaration since the declaration of the function with the "struct library" before the declaration of the functions

There is also a struct declaration mistake

in C, structures MUST have the keyword "struct" used all the time

so "struct library" refers to a structure named "library"

But in the code , there wasn't a structure named "library" at all

typedef struct { ... } library;

The above did not create structure named "library" so "struct library" must not be used in the code

What is created above is a NEW TYPE onto an anonymous structure and the new type is named "library"

just like

typedef int _INT32;

This is to create a NEW TYPE named "_INT32" and the type of it is analogous to an existing type named "int"

For the code to be correct, the order matters

first "typedef struct { ... } library;" should happen before the declaration of the functions having arguments using the new type.

Hence it should be

typedef struct { ... } library;

void function_1(library);

 

[ttl_64]

Compile and link no error reported?