c++ error: invalid types int[int] for array subscript

c++ error: invalid types int[int] for array subscript

c++ error: invalid types int[int] for array subscript

C++ inherits its syntax from C, and tries hard to maintain backward compatibility where the syntax matches. So passing arrays works just like C: the length information is lost.

However, C++ does provide a way to automatically pass the length information, using a reference (no backward compatibility concerns, C has no references):

template<int numberOfRows, int numberOfColumns>
void printArray(int (&theArray)[numberOfRows][numberOfColumns])
{
    for(int x = 0; x < numberOfRows; x++){
        for(int y = 0; y < numberOfColumns; y++){
            cout << theArray[x][y] <<  ;
        }
        cout << endl;
    }
}

Demonstration: http://ideone.com/MrYKz

Heres a variation that avoids the complicated array reference syntax: http://ideone.com/GVkxk

If the size is dynamic, you cant use either template version. You just need to know that C and C++ store array content in row-major order.

Code which works with variable size: http://ideone.com/kjHiR

Since theArray is multidimensional, you should specify the bounds of all its dimensions in the function prototype (except the first one):

void printArray(int theArray[][3], int numberOfRows, int numberOfColumns);

c++ error: invalid types int[int] for array subscript

Im aware of the date of this post, but just for completeness and perhaps for future reference, the following is another solution. Although C++ offers many standard-library facilities (see std::vector or std::array) that makes programmer life easier in cases like this compared to the built-in array intrinsic low-level concepts, if you need anyway to call your printArray like so:

printArray(sally, 2, 3);

you may redefine the function this way:

void printArray(int* theArray, int numberOfRows, int numberOfColumns){
    for(int x = 0; x < numberOfRows; x++){
        for(int y = 0; y < numberOfColumns; y++){
            cout << theArray[x * numberOfColumns + y] <<  ;
        }
        cout << endl;
    }
}

In particular, note the first argument and the subscript operation:

  • the function takes a pointer, so you pass the name of the multidimensional array which also is the address to its first element.
  • within the subscript operation (theArray[x * numberOfColumns + y]) we access the sequential element thinking about the multidimensional array as an unique row array.

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