How to pass a void function(void) in to another function as parameter in c

Question

[enter image description here][1]I have a function void readline() which output a string, and I want to pass it into another function as a parameter, how can I do that,

Thanks for any help.

int scorecount(argc1, argv1, void readline());
void readline();


int main(int argc, char *argv[]){
    scorecount(argc,argv);
}


int scorecount(argc1, argv1, void readline()){

    output a int
    and I want to use the string from readline function somewhere in
    scorecount

}


void readline(){

    output a string

}

You need to show more code, your question is unclear as it stands here. Or you may need to read your C text book. — Jabberwocky, Sep 15 '17 at 10:25
you are saying that readline will give u output string and you want to pass it into another function the that readline function return type should be "string" — Sandeep Bhaskar, Sep 15 '17 at 10:25
Maybe you want [GNU readline](http://cnswww.cns.cwru.edu/php/chet/readline/rltop.html) but it does not return a `void` — Basile Starynkevitch, Sep 15 '17 at 10:29
Why have you linked to the actual code, and typed in some distant approximation of that code? Please read about, and then provide, a [MCVE] in the text of your question. — ad absurdum, Sep 15 '17 at 11:57

Vlad from Moscow · Answer 1 · 2017-09-15T11:52:00.743

5

You can declare the parameter as the function declaration using any name of the parameter. For example

void another_function( void readline( void ) );

And the function another_function can be called like

another_function( readline );

The compiler adjusts the function declaration to pointer to the function. So the above declaration is equivalent to

void another_function( void ( *readline )( void ) );

EDIT: After you updated your code then the function should be declared like

int scorecount( int argc, char * argv[], void readline( void ) );
void readline( void );

and called like

scorecount( argc, argv, readline );

edited Sep 15 '17 at 11:52

answered Sep 15 '17 at 10:24

Vlad from Moscow

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I'm very new to Stack overflow, how can I put my code here so you guys can see it? – Hu Yunfei Sep 15 '17 at 10:48
@HuYunfei Is my answer unclear or do you have one more problem? – Vlad from Moscow Sep 15 '17 at 11:09
I want to pass readline func into a function which has already passed argc and argv in the parameter, and I applied your solution, error appears – Hu Yunfei Sep 15 '17 at 11:17
@HuYunfei Update your question. – Vlad from Moscow Sep 15 '17 at 11:23
@HuYunfei Do not give a reference to an image. Type the code in your question. – Vlad from Moscow Sep 15 '17 at 11:29
please see the screen shot of my code, thank you – Hu Yunfei Sep 15 '17 at 11:30
@HuYunfei Type the code an the error message in the question instead of providing a reference. – Vlad from Moscow Sep 15 '17 at 11:33
@HuYunfei Reread my answer. I showed how the function should be called. – Vlad from Moscow Sep 15 '17 at 11:43
I have put a piece of code here, please see it – Hu Yunfei Sep 15 '17 at 11:46

How to pass a void function(void) in to another function as parameter in c

1 Answers1