C++ printing array results - c++

Question

I was able to fix some of the errors. Now I am just getting 3.
1. control reaches end of non-void function at } before the
void displayIntegerArray(int *arrayPtr,int arraySize) function.
2. expected expression at delete[];.
3. expected expression at return 0;.
#include <iostream>
#include <iomanip>
using namespace std;
// Function prototypes
void populateIntegerArray(int *arrayPtr, int arraySize);
void displayIntegerArray(int *arrayPtr, int arraySize);
void findMaximumInteger(int *arrayPtr, int arraySize);
//method to populate array
void populateIntegerArray(int *arrayPtr,int arraySize)
{
for(int i=0;i<arraySize;i++)
{
cout<<"Enter value for array element:"<<i<<":";
cin>>arrayPtr[i]; //reading value
}
}
void findMaximumInteger(int *arrayPtr,int arraySize)
{
int maximum = arrayPtr[0];
{
for(int i=0;i<arraySize;i++)
{
if(maximum<arrayPtr[i])maximum=arrayPtr[i];
}
cout<<"Maximum integer in array is: "<<maximum<<endl;
}
}
void displayIntegerArray(int *arrayPtr,int arraySize)
{
for(int i=0;i<arraySize;i++)
{
cout<<&arrayPtr[i]<<": arrayPtr["<<i<<"] = "<<setw(15)<<arrayPtr[i]<<endl;
}
}
int main()
{
int arraySize;
// Read array size
cout<<"Enter desired array size:";
cin>>arraySize;
// Print array
cout<<"arrayPtr = "<<arraySize<<endl;
populateIntegerArray( arrayPtr, arraySize);
displayIntegerArray(arrayPtr, arraySize);
findMaximumInteger( arrayPtr, arraySize);
cout<<"DELETING array at arrayPtr = "<<arrayPtr<<endl;
delete[];
return 0;
}

Answer 1

In main function:
There is undeclared variable; arrayPtr.
So you have to declare it and allocate memory for it dynamically.
int* arrPtr = new int[arraySize];
You also have to provide the delete [] operator the arrayPtr to free the memory allocated.
Finally main function will be like that:
int main()
{
int arraySize;
// Read array size
cout<<"Enter desired array size:";
cin>>arraySize;
int *arrayPtr=new int[arraySize];
// Print array
cout<<"arrayPtr = "<<arraySize<<endl;
populateIntegerArray( arrayPtr, arraySize);
displayIntegerArray(arrayPtr, arraySize);
findMaximumInteger( arrayPtr, arraySize);
cout<<"DELETING array at arrayPtr = "<<arrayPtr<<endl;
delete[] arrayPtr;
return 0;
}

Answer 2

So there are a couple of things that ain't quite right with your program my dude, but they mainly stem from you not creating a arrayPtr in main. If you don't create something to point to a chunk of memory then your program wont know where the array is.
https://www.cplusplus.com/doc/tutorial/pointers/
The next problem is that, because you never created the pointer to the memory, you also forgot to create the space for the memory. If the array was the same size every time your program ran and was reasonably small then you could just allocate the space on the stack. However you don't so you need to allocate the memory dynamically. This means that you need to ask your operating system for the memory and get back its location. This can be done with the new[] operator. Then when you are done using the memory you tell the program to de-allocate it with the delete[] operator. (If you don't then memory will keep being marked as used despite your program ending. This is called a memory leak.)
https://www.cplusplus.com/doc/tutorial/dynamic/
Next you aren't actually displaying the location of the array. You want to print the new arrayPtr variable to see the location.
Lastly your post is a bit hard to work with. The formatting is a bit inconstant and that makes it significantly harder to read. Luckily your program was simple enough that it isn't too time consuming to read through and figure out what is going wrong. However, as your programs get more complex and larger, many people won't be willing to look through your whole program and find your bugs for you. Try to narrow down where you think the error is coming from and post: some context, the relevant chunk of code, and the exact error messages.