Question

Having trouble returning array pointers from a function. Not sure how exactly to do it properly.

eg.
char * returnArray(char string[])
{
return string;
}

I'm unsure if I have to make a pointer variable. I get warnings if I try to return &string.

Answer 1

Are you calling it with the string? If so, that is a call by reference and no return is needed.

Answer 2

I'm doing something like this:
char * returnCharPtr(char string[])
{
char otherString[20] = "bonjour monsieur";
char *c_ptr;
strcpy(otherString,string);

c_ptr = &otherString;

printf("returning %s", otherString);

return c_ptr;
}

This is my attempt so far at making a a function return a pointer. I'm unsure if the pointer variable is necessary here. I need it to return the pointer to the array so that the array will be able to be assigned as another array.

eg.
int main(){
char somestring[20] = returnArray(string);
}

Answer 3

You can just make the array, then pass by reference to fill it.

Here is an old project of mine:
http://pastebin.com/6aEFrGtS

Note the declaration of: `void psudoStats(long double arr[], int x);` and then how the array is used in it. Even though it is a void, I am using this to fill the array.

```
void psudoStats(long double arr[], int x)
{
int sd3, sd2, sd1, i, j;

srand (time(NULL));

sd3 = x / 5;
sd2 = x / 27;
sd1 = x - sd2 - sd3;

for (i = 0; i < x; i++)
{
for (j = 0; j < sd3; j++)
{
arr[i] = static_cast<long double>(9500.0 + (rand() % 500));
if (i % 2) arr[i] *= -1.0;
}

for (j = 0; j < sd2; j++)
{
arr[i] = static_cast<long double>(6800.0 + (rand() % 2700));
if (i % 2) arr[i] *= -1.0;
}

for (j = 0; j < sd1; j++)
{
arr[i] = static_cast<long double>((rand() % 6800));
if (i % 2) arr[i] *= -1.0;
}
arr[i] /= 100.0;
}
}// end psudoStats
```

Answer 4

See, you don't pass an array. Never have in c/c++. You pass a pointer to the array. That has a whole world of implications.

"At some moment we may need to pass an array to a function as a parameter. In C++ it is not possible to pass a complete block of memory by value as a parameter to a function, but we are allowed to pass its address. In practice this has almost the same effect and it is a much faster and more efficient operation." From:
http://www.cplusplus.com/doc/tutorial/arrays/

Answer 5

Its_Sonic, there's also one other problem with your example: otherString is declared in the function. When the function returns, it's execution frame is reclaimed/destroyed, so a pointer into that area points to garbage.

Answer 6

Ah, good point. I forgot to mention garbage collection!

Answer 7

@Its_Sonic Do you want any more help?

Answer 8

Is this C or C++?

Answer 9

Not sure. IS has not replied in a while....