how come compiler is displaying this problem even though I've declared the array.

```
#include <iostream>
#include <conio.h>
using namespace std;
void toBinary(long long decimal, int binary_number_array[], int & NumBinaryBits);
int main()
{
long long decimalNumberToConvert[1] ;
cout<<"Enter a decimal number"<<endl;
cin>>decimalNumberToCovert[1];
int sizeBinaryNumber, binaryNumberArray[100];
toBinary(decimalNumberToConvert, binaryNumberArray, sizeBinaryNumber);
//Printing out the binary number
cout << " The binary equivalent of " << decimalNumberToConvert << " : ";
for (int i = 0; i < sizeBinaryNumber; ++i)
cout << binaryNumberArray[i];
cout <<endl;
getch();
return 0;
}
void toBinary(long long decimal, int binary_number_array[], int & NumBinaryBits)
{
long long decimalNumberToConvert[1] = decimal;
NumBinaryBits = 0;
do
{
binary_number_array[NumBinaryBits++] = decimalToConvert % 2;
decimalNumberToConvert[1] /= 2;
}
while (decimalToConvert);
for (int i = 0; i <= NumBinaryBits / 2; ++i) std::swap(binary_number_array[i], binary_number_array[NumBinaryBits - i - 1]);}
```