Why this error " pngrutil.c:27:error: expected ‘;’, ‘,’ or ‘)’ before ‘=’ token" in the following function?

Question

double shrDelta(int iCounterID = 0){     //this is the 27  the line

    double DeltaT;            
    static struct timeval _NewTime;  
    static struct timeval _OldTime[3]; 
    gettimeofday(&_NewTime, NULL);  

    if (iCounterID >= 0 && iCounterID <= 2)
        {        

        DeltaT =  ((double)_NewTime.tv_sec + 1.0e-6 * (double)_NewTime.tv_usec) - ((double)_OldTime[iCounterID].tv_sec + 1.0e-6 * (double)_OldTime[iCounterID].tv_usec);        

        _OldTime[iCounterID].tv_sec  = _NewTime.tv_sec;     
        _OldTime[iCounterID].tv_usec = _NewTime.tv_usec;        
        }   
    else        
        {         

        DeltaT = -9999.0;       
        }     

    return DeltaT;
}

The function is supposed to return the time elapsed between last two calls.

You can't put an assignment in the parameter list of a function in C. — Barmar, Apr 10 '14 at 08:09
I think you're confusing C with some other languages that allow you to specify default arguments this way. — Barmar, Apr 10 '14 at 08:09
Generally it is good form to explain the issue you are getting and then ask a question in the body of the text. — Rob Baillie, Apr 10 '14 at 08:09
the function is working fine in a cpp file, but i just copied the whole function in a .c file — Piyush Kumar, Apr 10 '14 at 08:23

score 3 · Accepted Answer · answered Apr 10 '14 at 08:10

3

C does not support defaulting of function parameters (or function overloading for that matter).

You need to write

double shrDelta(int iCounterID)

instead and always call the function with the parameter value explicitly given.

answered Apr 10 '14 at 08:10

Bathsheba

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score 2 · Answer 2 · edited May 23 '17 at 10:33

2

C standard doesnt support default values. what you used is a C++ concept. you can read this related question

edited May 23 '17 at 10:33

Community

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answered Apr 10 '14 at 08:11

LearningC

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Why this error " pngrutil.c:27:error: expected ‘;’, ‘,’ or ‘)’ before ‘=’ token" in the following function?

2 Answers2