Static Variables

[Anmol444]

From my book


"There are some things you can’t do with automatic variables within a function. You can’t count how many times a function is called, for example, because you can’t accumulate a value from one call to the next. There’s more than one way to get around this if you need to. For instance, you could use a reference parameter to update a count in the calling program, but this wouldn't help if the function was called from lots of different places within a program."

How will it not help if the function is called from many places in the program?

Is it because maybe the scope of the variable used will end?

[Yanson]

I think it means if you call the function from within another function, it might not be possible to pass the same variable to the function.

[Anmol444]

No but you are taking it as a reference, you should be able to.

[giblit]

maybe he means that you can actually keep track of the number of times a function is called by using a static variable try this

void staticFunction( void )
{
    static short calls = 0; //static is only initialized once kind of like a global
    calls++;
    std::cout << "This function has been called " << calls << " times!" << std::endl;
}

void autoFunction( void )
{
    short calls = 0; //gets initialized each time
    calls++;
    std::cout << "This function has been called " << calls << " times!" << std::endl;
}

int main( int argc , char** argv )
{
    for( unsigned int i = 0; i < 10; i++ )
    {
        staticFunction();
    }

    for( unsigned int i = 0; i < 10; i++ )
   {
        autoFunction();
    }
}

I'm not sure exaclty what he means maybe he means like it will seem like it jumps if it is called a bunch of times in different functions at one time maybe?

[Anmol444]

Also he means without it being static, without calls being static lol.

[giblit]

Oh ya I wasn't really reading it all I.just saw static

[Daleth]

void funky(int &count){
   count++;
   std::cout << "I have been called " << count << " times so far..." << std::endl;
}
void funky2(){
   int callnumber(0);
   for(int I=0; I < 20; I++)   funky(callnumber);
}
void funky3(){
   int callnumber(0);
   for(int I=0; I < 5; I++)   funky(callnumber);
}

So what is the total number of times funky has been called? Is it 20? 5? Or 25?
Without using static variables, the message printed out from funky is misleading.