Counting lowercase, uppercase in string and array

#include <iostream>
#include <iomanip>
#include <string>
#include <fstream>
#include <cstdlib>

using namespace std;

// Prototypes 
bool ReadStringsFile(string fileName, string ArrayOfStrings[], int &number_of_lines);
void PrintStringArray(int number_of_lines, string ArrayOfStrings[]);
int CountWordsInArray(int number_of_lines, string ArrayOfStrings[]);
int CountWordsInString(string InputString);
int CountCharactersInString(string InputString);
int CountCharactersInArray(int number_of_lines, string ArrayOfStrings[]);
int CountUpperCaseCharactersInArray(int number_of_lines, string ArrayOfStrings[]);
int CountLowerCaseCharactersInArray(int number_of_lines, string ArrayOfStrings[]);
int CountPunctuationCharactersInArray(int number_of_lines, string ArrayOfStrings[]);

string LongestLineOfTextInArray(int number_of_lines, string ArrayOfStrings[]);
string ShortestLineOfTextInArray(int number_of_lines, string ArrayOfStrings[]);

int main()
{
    int number_of_lines = 0;
    int word_count = 0;
    int character_count = 0;
    int uppercase_letter_count = 0;
    int lowercase_letter_count = 0;
    int punctuation_count = 0;
    string filename = "testfile.txt";
    string ArrayOfStrings[500];
    string longest_string;
    string shortest_string;

    if ((ReadStringsFile(filename, ArrayOfStrings,
        number_of_lines)) != true)
    {
        cout << "Can not Read File: " << filename << endl;
        exit(-1);
    }

    CountWordsInString(filename);
    PrintStringArray(number_of_lines, ArrayOfStrings);
    CountCharactersInString(filename);
    character_count = CountCharactersInArray(number_of_lines, ArrayOfStrings);
    word_count = CountWordsInArray(number_of_lines, ArrayOfStrings);
    longest_string = LongestLineOfTextInArray(number_of_lines, ArrayOfStrings);
    shortest_string = ShortestLineOfTextInArray(number_of_lines, ArrayOfStrings);
    uppercase_letter_count = CountUpperCaseCharactersInArray(number_of_lines, ArrayOfStrings);
    lowercase_letter_count = CountLowerCaseCharactersInArray(number_of_lines, ArrayOfStrings);
    punctuation_count = CountPunctuationCharactersInArray(number_of_lines, ArrayOfStrings);

    cout << "" << character_count << endl;
    cout << "" << word_count << endl;
    cout << "" << longest_string << endl;
    cout << "" << shortest_string << endl;
    cout << "" << uppercase_letter_count << endl;
    cout << "" << lowercase_letter_count << endl;
    cout << "" << punctuation_count << endl;

    cout << "" << number_of_lines << endl;
    system("PAUSE");
    return 0;
}


void PrintStringArray(int number_of_lines, string ArrayOfStrings[])
{
    for (int iii = 0; iii <number_of_lines; iii++)
    {
        cout << "" << ArrayOfStrings[iii] << "\n" << endl;
    }
}

// This function Counts all characters in Array.
int CountCharactersInArray(int number_of_lines, string ArrayOfStrings[])
{
    return -1;
}

// This function counts "words" in the array.
int CountWordsInArray(int number_of_lines, string ArrayOfStrings[])
{
    return -1;
}

// This function takes a string and counts the "words" in that string
int CountWordsInString(string InputString)
{
    return -1;
}

// This function returns the count of the characters in a string
int CountCharactersInString(string InputString)
{
    return InputString.length();
}

// This function counts the number of upper case letters in the Array/File
int CountUpperCaseCharactersInArray(int number_of_lines, string ArrayOfStrings[])
{
    int i = 0; int uppercase = 0;

    return uppercase;
}

// This function counts the number of lower case letters in the Array/File
int CountLowerCaseCharactersInArray(int number_of_lines, string ArrayOfStrings[])
{
    int cCount(0);

    return -1;
}

// This function counts the number of punctuation characters in the Array/File
int CountPunctuationCharactersInArray(int number_of_lines, string ArrayOfStrings[])
{
    return -1;
}

// This function finds the Longest line of text in the Array
string LongestLineOfTextInArray(int number_of_lines, string ArrayOfStrings[])
{
    return 0;
}

// This function finds the Shortest line of text in the Array
string ShortestLineOfTextInArray(int number_of_lines, string ArrayOfStrings[])
{
    return 0;
}


bool ReadStringsFile(string fileName, string ArrayOfStrings[],
    int &number_of_lines)
{
    string input_line;
    ifstream infile(fileName.c_str());

    if (!infile)
    {
        return false;
    }

    number_of_lines = 0;
    while (getline(infile, input_line))
    {
        ArrayOfStrings[number_of_lines] = input_line;
        number_of_lines = number_of_lines + 1;
    }

    return true;
}

Written above is the code I am currently working on, and I most of the template written. The problem I am attempting to solve is to finish these function prototypes and have them do what they describe. What this program will do, is load a text document with a bunch of random sentences written out, read that file into the program, and complete the functions based on it such as how many lowercase, uppercase, etc. Where my confusion is, is asking me to count the number of words in the array as well as in the string. I do not understand the differences between these two functions.