I have an exercise that I need help with. It is about recursion. The questions are attached as pdf. There are some important rules regarding for this assignment that are also mentioned in the pdf. Also, since its a relatively beginner level course, I can not understand use of some advanced material like pointers. There are 5 functions to program in total. I would also like to get the code for first 2 functions within 2 days. The skeleton code is given below.

#include <iostream>
using namespace std;
//you are NOT allowed to include any additional library
const int ARRAY_MAX_SIZE = 12;

//given; do NOT modify; please refer to the webpage description
void printArray(int array[], int arraySize, int currentPosition)
{
    cout << array[currentPosition];
    if(currentPosition < arraySize-1)
    {
        if(array[currentPosition+1] > 0)
            cout << "+";
        printArray(array, arraySize, currentPosition+1);
    }
    else
        cout << endl;
}

//given; do NOT modify; please refer to the webpage description
void printArray(int array[], int arraySize)
{
     printArray(array, arraySize, 0);
}

//***** Only write your code below this line, remember that NO loop is allowed! ***** 
int arraySum(int array[], int arraySize)
{
    return 0;  //change this line if you want
}

bool solve(int input[], int size, int target, int result[], int& resultSize) 
{
    return false;  //change this line if you want
}

void printString(const char str[])
{
}

int getIntValue(const char str[], int start, int end)
{
    return 0;  //change this line if you want
}

int evaluate(const char str[])
{
    return 0;  //change this line if you want
}
//***** Only write your code above this line, remember that NO loop is allowed! *****
int main()
{
    int testCase;
    cout << "Hi, recursion master! Which test case do you want to run?" << endl;
    cin >> testCase;

    cout << endl << "Test case " << testCase << " output:" << endl;
    cout << "===================================" << endl;

    if(testCase == 0) //this test case is used to show you how printArray works; it is NOT used to grade your work and it is NOT on ZINC; no mark is allocated to this; try it on your own computer if you want
    {
        int array1[] = {1, 2, 3};
        printArray(array1, 3);
        int array2[] = {1, 2, 3, -4};
        printArray(array2, 4);
        int array3[] = {-8, 2, 1, -4};
        printArray(array3, 4);
        int array4[] = {99};
        printArray(array4, 1);
        int array5[] = {-1199};
        printArray(array5, 1);
    }
    
    else if(testCase == 1) //test arraySum
    {
        int array[] = {1, 2, 3};
        cout << arraySum(array, 3) << endl;
    }
    else if(testCase == 2) //test arraySum
    {
        int array[] = {-1, -234, 33, 5};
        cout << arraySum(array, 4) << endl;
    }

    else if(testCase == 3) //test solve
    {
        int input[] = {1, 2, 3, 4};
        int size = 4;
        int target = 2;
        int result[ARRAY_MAX_SIZE] = {}; //filled with ''
        int resultSize = 0;
        if(solve(input, size, target, result, resultSize))
        {
            cout << "solved: ";
            printArray(result, resultSize);
        }
        else
            cout << "no solution!" << endl;
    }
    else if(testCase == 4) //test solve
    {
        int input[] = {1, 2, 3, 4};
        int size = 4;
        int target = -2;
        int result[ARRAY_MAX_SIZE] = {}; //filled with ''
        int resultSize = 0;
        if(solve(input, size, target, result, resultSize))
        {
            cout << "solved: ";
            printArray(result, resultSize);
        }
        else
            cout << "no solution!" << endl;
    }
    else if(testCase == 5) //test solve
    {
        int input[] = {1, 2, 3, 4};
        int size = 4;
        int target = -9;
        int result[ARRAY_MAX_SIZE] = {}; //filled with ''
        int resultSize = 0;
        if(solve(input, size, target, result, resultSize))
        {
            cout << "solved: ";
            printArray(result, resultSize);
        }
        else
            cout << "no solution!" << endl;
    }
    else if(testCase == 6) //test solve
    {
        int input[] = {8, 13, 1, 3, 5, 9};
        int size = 6;
        int target = 9;
        int result[ARRAY_MAX_SIZE] = {}; //filled with ''
        int resultSize = 0;
        if(solve(input, size, target, result, resultSize))
        {
            cout << "solved: ";
            printArray(result, resultSize);
        }
        else
            cout << "no solution!" << endl;
    }
    else if(testCase == 7) //test solve
    {
        int input[] = {88, 13, 1, 3, 5, 9};
        int size = 6;
        int target = 9;
        int result[ARRAY_MAX_SIZE] = {}; //filled with ''
        int resultSize = 0;
        if(solve(input, size, target, result, resultSize))
        {
            cout << "solved: ";
            printArray(result, resultSize);
        }
        else
            cout << "no solution!" << endl;
    }
    else if(testCase == 8) //test solve
    {
        int input[] = {888, 13333, 20000, 1, 99, 3, 5, 9, 33, 44, 55, 100};
        int size = 12;
        int target = -165;
        int result[ARRAY_MAX_SIZE] = {}; //filled with ''
        int resultSize = 0;
        if(solve(input, size, target, result, resultSize))
        {
            cout << "solved: ";
            printArray(result, resultSize);
        }
        else
            cout << "no solution!" << endl;
    }

    else if(testCase == 9) //test printString
    {
        printString("1+1-2+1234");
    }
    else if(testCase == 10) //test printString
    {
        printString("Wow this assignment is so much fun!!!");
    }

    else if(testCase == 11) //test getIntValue
    {
        char str[] = "567";
        cout << getIntValue(str, 0, 2) << endl;
    }
    else if(testCase == 12) //test getIntValue
    {
        char str[] = "567";
        cout << getIntValue(str, 0, 1) << endl;
    }
    else if(testCase == 13) //test getIntValue
    {
        char str[] = "567";
        cout << getIntValue(str, 0, 0) << endl;
    }
    else if(testCase == 14) //test getIntValue
    {
        char str[] = "abc567abc";
        cout << getIntValue(str, 4, 5) << endl;
    }
    
    else if(testCase == 15) //test evaluate
    {
        cout << evaluate("172") << endl;
    }
    else if(testCase == 16) //test evaluate
    {
        cout << evaluate("3+2") << endl;
    }
    else if(testCase == 17) //test evaluate
    {
        cout << evaluate("1+2-4") << endl;
    }
    else if(testCase == 18) //test evaluate
    {
        cout << evaluate("11+21-43") << endl;
    }
    else if(testCase == 19) //test evaluate
    {
        cout << evaluate("11+21-43+888") << endl;
    }
    else if(testCase == 20) //test evaluate
    {
        cout << evaluate("-21") << endl;
    }
   
    cout << "===================================" << endl;

    return 0;
}