2 dimension array to a function does not pass correctly in C++

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I have been trying to pass the 2 dimension array to a function and the array recieved in the function is just random characters

C++

void SomeFunction(char arr[][50])
{
   //arr is just random strings
}

int main()
{
  char arr[50][50] = { {"Hello"}, {"World"} };
  SomeFunction(arr);
}

What I have tried:

I have tried googling and stuff and did whatever it said and it still doesn't work

Posted 4-Mar-20 2:35am

Harasees_Singh

Updated 4-Mar-20 4:10am

v2

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Stefan_Lang 4-Mar-20 10:56am

I've added this line to SomeFunction() in onlinegdb compiler (https://www.onlinegdb.com/online_c++_compiler):
cout << arr[0] << endl << arr[1] << endl;

This outputs
Hello
World

So what is your question?

2 solutions

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Patrice T · Accepted Answer · 2020-03-04T02:38:00

Solution 1

C++

char arr[50][50] = { {"Hello"}, {"World"} };

You need to understand that a string is an array of chars.
So your code is a list of list of strings which means a list of list of list of chars.
And a string is a zero terminated list of chars.
Try:

C++

char arr[50][50] = { "Hello", "World" };

Posted 4-Mar-20 2:38am

Patrice T

Updated 4-Mar-20 2:42am

v2

OriginalGriff · Accepted Answer · 2020-03-04T04:10:00

Solution 2

To add to what Patrice T says, try this:

void SomeFunction(char arr[][50])
{
    for (int i = 0; i < 50; i++)
    {
        if (arr[i][0] != '\0')
        {
            cout << arr[i] << "\n";
        }
    }
}

int main()
{
  char arr[50][50] = { {"Hello"}, {"World"} };
  SomeFunction(arr);
  return 0;
}

It'll print just the strings you added when you declared the array.

Posted 4-Mar-20 4:10am

OriginalGriff

Comments

Patrice T 4-Mar-20 10:49am

Hi OG,
Are you sure about the:

char arr[50][50] = { {"Hello"}, {"World"} };

OriginalGriff 4-Mar-20 10:53am

Absolutely. It allocates space for 50 strings of 50 characters and populates two of them with copies of the string literals.

It's been a while since I did much with C / C++, so I checked with an online compiler:
https://www.onlinegdb.com/online_c++_compiler

Patrice T 4-Mar-20 11:52am

OK, I take note of this counter intuitive syntax, another reason to not use C++ :)

Stefan_Lang 4-Mar-20 10:57am

onlinegdb accepts it just fine: https://www.onlinegdb.com/online_c++_compiler