Question

[C++ Programming Question]

I tried to find my middle value in my array. So, I tried to use

sizeof(array) / sizeof(array[0])

but it is not working as well

Could you help me to fix it?

My middle value function located at void middleValue(int array[]) << here

Here is my code

#include 
#include  // Input/Output with Files , ifstream(read from file) + ofstream(write on file)


using namespace std;

class Random
{
    private:

    public:

        void allValues(int array[])
        {
            cout << "Show all values" << endl;

            for(int i =0; i < 1000; i++)
            {
                cout << array[i] << endl;
            }


        }

        void sumValues(int array[])
        {
            cout << "Output the sum of all values" << endl;

            int sum = 0;

            for(int i = 0; i < 1000; i++)
            {
                sum += array[i];
            }

            cout << sum < highValue)
                {
                    highValue = array[i];
                }
            }

            cout << highValue < array[j+1])
                    {
                        temp=array[j];

                        array[j]=array[j+1];

                        array[j+1]=temp;
                    }
                }

            }
            cout << "Output all values thar sorted in Bubble sort" << endl;

            for(int k = 0; k < 1000; k++)
            {
                cout << array[k] << endl;
            }



        }

        void linearSearch(int array[])
        {
            int searchValue, flag;

            cout << "Input what values do you want to find: " << endl;
            cin >> searchValue;
            flag = 0;

            for(int i = 0; i < 1000; i ++)
            {
                if(array[i] == searchValue)
                {
                    cout << searchValue << "is located at" << i+1 << endl;
                    flag = 1;
                    //return;
                }
            }
            if(!flag)
            {
             cout << searchValue << "is not exsited in array" << endl;
            }
        }
};

int main() {
    int ranNum; //random number
    const int arraySize = 1000; // Fixed array size
    int array[arraySize];
    int choice; // Used in Menu Part

    ofstream outfile; //Write on File
    outfile.open("randomfile");

    srand(time(0)); // producing a series of pseudo-random integers

/**If we generate a sequence of random number with rand() function,
it will create the same sequence again and again every time program runs
*/
    cout << "Writing data to file..." << endl;

    for (int i = 0; i < 1000; i++) {

        ranNum = (rand() % 1000) + 1;
        //cout << ranNum << "\n";
        outfile << ranNum << "\n";
    }
    outfile.close();

    ifstream file;
    file.open("randomfile");


    file.seekg(0, ios::beg);

    cout << "Reading data from file..." << endl;
    for (int i = 0; i < 1000; i++) {
        file >> array[i]; // Push into my array
    }

    file.close();

    cout << "===========================================================" << "\n";

    Random rd; // random rd is not working wtf?

    /**
* Here while passing the array as parameter, we just need to send
* the name of the array without its size
*/

    do
    {



        cout << "1.Show  All Values" << endl;
        cout << "2.Show Sum of All Values" << endl;
        cout << "3.Show All Odd Values" << endl;
        cout << "4.Show All Even Values" << endl;
        cout << "5.Show Middle Value" << endl;
        cout << "6.Show First Element value" << endl;
        cout << "7.Show Last Element Value" << endl;
        cout << "8.Show Highest Value" << endl;
        cout << "9.Show Lowest Value" << endl;
        cout << "10.Sorting array by using bubble sort" << endl;
        cout << "11.Finding value by using Linear Search" << endl;
        cout << "12.Terminate Program" << endl;
        cout << "Input Your Choice: " << endl;
        cin >> choice;


            switch(choice)
            {
                case 1:
                    rd.allValues(array);
                    break;
                case 2:
                    rd.sumValues(array);
                    break;
                case 3:
                    rd.oddValue(array);
                    break;
                case 4:
                   rd.evenValue(array);
                   break;
                case 5:
                    rd.middleValue(array);
                    break;
                case 6:
                    rd.firstValue(array);
                    break;
                case 7:
                    rd.lastValue(array);
                    break;

                case 8:
                    rd.highestValue(array);
                    break;
                case 9:
                    rd.lowestValue(array);
                    break;
                case 10:
                    rd.sortValue(array);
                    break;
                case 11:
                    rd.linearSearch(array);
                    break;
                case 12:
                    cout << "Terminate Program" << endl;
            }
    }while(choice != 12);








    return 0;


}

Answer 1

void middleValue(int array[])

{

int size=sizeof(array);

cout<<size;

}

When the above function was called it always prints 8 .

Because sizeof(arr) is returning the size of a pointer variable.

1) sizeof() returns the size of the array when the base address of an array is passed to it.

2 )But you're declaring " array[] " in the function definition ------> void middleValue(int array[]) .

3) void middleValue(int array[]) is actually equals to the void middleValue(int *array)

In the function, array doesn't act as a base address instead it acts as a pointer to an array.

As it was an array, sizeof() is returning the size of a pointer varaible.

I hope you understand this.....If you do not understand, feel free to comment.

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