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cfunctionpointers
Sen ZmaKi
Sen ZmaKi

Reputation: 160

Trying to make a function return two values using pointers but I'm getting the error: expected an identifier

It's supposed to be function that returns two random numbers depending on a range chosen by the user, I read I could use pointers to return two values from a function but I get the error expected an identifier right before int* ran1 and int* ran2and when I run the code I get the error expected ')' before 'int' Both ran1 and ran2 are global variables. Even when I use different names for the pointers I still get the same error.

int level(lev, ran1, ran2, int* ran1, int* ran2){
    srand(time(0));
    if(lev == 'l'){
            ran1=(rand()%10+1);
            ran2=(rand()%10+1);
    }
    if(lev == 'm'){
        ran1=(rand()%50+11);
        ran2=(rand()%50+11);
    }
    if(lev == 'h'){
        ran1=(rand()%100+51);
        ran2=(rand()%100+51);
    }
}

Upvotes: 0

Views: 87

Answers (1)

ryyker
ryyker

Reputation: 23208

"I get the error expected an identifier right before int* ran1 and int* ran2"

The C compiler error message phrase "expected an identifier" is seen for many syntactical errors, across a wide variety of compilers (even for other languages) In this case the compiler is squawking about following typed variables with untyped variables. This

int level(lev, ran1, ran2, int* ran1, int* ran2){
          ^^^ untyped ^^^  ^^^^ typed ^^^^^^^^^

Although rarely used today this antiquated syntax, when accepted by some C compilers, is to provide backward compatibility with older versions of the C language. Silence the compiler by surrounding the untyped with parenthesis:

int level((lev), int* ran1, int* ran2){

(Note ran1 and ran2, removed. Even if somehow legal in positions 2 & 3 would result in multiple definition of the same variables in position 4 & 5)

An aside, not all of the parameters are necessary to accomplish what your code example is doing. The code below shows removes those that are not needed.

Note, when passing a int pointer to be updated, its value needs to be updated, which in this case will be *ran1 or *ran2, not ran1 or ran2.

(the * symbol when used in this context de-references a pointer, and in this example, the de-referenced pointer is the value to be updated.)

Also, as pointed out in comments, srand() needs only to be called once during a program session, and should be seeded such that if the program has a short run-time duration, and may be called in quick succession, will have a unique seed value for each call.

The following illustrates these corrections in your code:

int level(int lev, int *ran1, int *ran2){//removed unused parameters
    //srand(clock());//moved to main, so just called once
    if(lev == 'l'){
            *ran1=(rand()%10+1);//Updating value *ran1 not pointer ran1 (apply to all)
            *ran2=(rand()%10+1);
    }
    if(lev == 'm'){
        *ran1=(rand()%50+11);
        *ran2=(rand()%50+11);
    }
    if(lev == 'h'){
        *ran1=(rand()%100+51);
        *ran2=(rand()%100+51);
    }
    return 0;//prototype requires a return statement
             //alternatively, the prototype can be made void
             //as 'level(...)' returns its work via its parameters.
}

int main(void)
{
    //calling this only once per execution, 
    srand(GetTickCount());//number of milliseconds elapsed since system started,
    
    int lev = 1, ran1, ran2;
    
    level(lev, &ran1, &ran2);
    
    return 0;//int main(void) requires a return statement
}

Upvotes: 2

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