Passing Array to a Function

take a look

Code:

---

#include <iostream>
using namespace std;

void input (int test[5])
{
int i;
for(i=0;i<5;i++)
{
cout<<"Enter a number: ";
cin>>test[i];
}
}
int main()
{
int array[5];
input(array);
for(int i=0;i<5;i++)
{
cout<<array[i]; //shows the same values that i have input using the //function
cout<<endl;
}
return 0;
}

---

I am passing array to function but it is being passed by reference..Could you please explain this concept?
Why is this being passed as reference even though i am not using & operator to pass it as reference. I wrote a bubble sort algorithm using the same concept and i passed the array to function and did not return anything but it sorted the array in my main function which is weird as i did not pass the array by reference. I passed it like in the above program.
Could you guys please explain this?I've been trying to find answer on Google but haven't been able to find it yet.Hopefully you guys can help.

Arrays are always passed as a pointer to the first element.

It's as if you did
input( &array[0] );

Which happens regardless of whether you declare your function as
void input (int test[5])
or
void input (int test[])
or
void input (int *test)

Quote:

---

Originally Posted by Salem

Arrays are always passed as a pointer to the first element.

It's as if you did
input( &array[0] );

Which happens regardless of whether you declare your function as
void input (int test[5])
or
void input (int test[])
or
void input (int *test)

---

Thank you for the explanation.So it is basically passing the address of the first element of the array to the function and then function is able to increment to next element address?..Also, I wrote this little function for my program.Could you please explain what this would return and whether i should remove this line?

Code:

---

int randomfunc (int random[3][3])
{   
    int rno=5;                                       
    for(row=0;row<3;row++)                                    for(column=1;column<3;column++){               
            random[row][column]=rno%10;
    rno=5+3;
        }

    return random[3][3]; //What would this return?
}
void main()
{
int array[3][3];
array[3][3]=randomfunc(array);
}

---

It does seem to be producing the correct output (i.e my array now contains random numbers..but could you please explain what would be returned by return random[3][3] and whether i should include it or not?

I dunno, I was encouraged by your first post with int main, despite your username.

Sadly, post #3 regresses back to the dark ages.

> return random[3][3]; //What would this return?
Garbage.
The max valid subscript for your array is random[2][2], so you're well off into the weeds with this one.

The assignment in main isn't any better.

So first, change back to int main. SourceForge.net: Void main - cpwiki
And secondly, what you are trying to achieve? Returning an array?

Quote:

---

Originally Posted by Salem

Which happens regardless of whether you declare your function as
void input (int test[5])
or
void input (int test[])
or
void input (int *test)

---

Just to highlight that the size is actually not checked if you use the first so there is no actual reason to put it. It matters for a 2D array where you need to put the "minor" dimension like "[][X]".

This also means that the function won't know the exact size of the array and that can be problematic. As you saw, you were accessing [3][3] which is invalid. Well, even if you do [2][2] then if the input is actually a 1x2 array then you can just create a buffer overflow if the function is used for a user input for example.

That is why std::vector (and std::array in C++11) are preferred.