Displayed errors

i have some programs i am working on and i am getting errors i figured some out but not quite all so if someone can overlook it and point me in the right direction......

Code:

a) void displayNum (  int  ); // my corrections: "displayMessage" and ";" 
       { 
            cout << num <<endl;
            return 0;
        }    

b)     #include <iostream>;// ";"
        using std::cout;
        using std::endl;
        arraySize = 10;          //declaration not specific
        myArray [ arraySize ] = { 0 };
        for ( int i = 0;  i < 11; i++)
        myArray [ i ] = 2 * i;

c)    int a[ 3 ] = { 1, 2, 3 };
       int num ;
       int *aPtr;
       aPtr = &a;
       aPtr ++;
       num = aPtr;

Those are not programs.
They are random snippets with various syntax errors.

Post actual programs and your actual error messages (Not "and i am getting errors").