用户输入字符串后，程序不计算函数

我的程序遇到了一个问题。这里的程序应该接受一个指向C字符串的指针作为参数，并计算字符串中包含的单词数以及字符串中的字母数。这两个值都应该传递回主函数，但不使用全局变量。在这个函数之后，我应该编写另一个函数，它接受字母数和单词数，并将每个单词的平均字母数（或平均单词大小）发送回主函数。我写的函数应该完成上述所有功能，并且从计数中排除标点符号和空格。不过，我遇到的问题是，当我以用户身份输入字符串并按enter键时，不会发生计算。我可以一直按回车键，直到没有尽头，但我不明白为什么会发生这种情况。任何见解都将不胜感激，我是指针和C字符串的新手。

这是我的代码：

#include <iostream>
#include <cstring>
#include <iomanip>
using namespace std;
void Count_All(char*, int&, double&, int&); // Function prototype.
double Calc_Average (char*, int, int, double); // Function prototype.
int main()
{
    const int size = 500;
    char userString[size];
    int Word = 0;
    int Pun = 0;
    double Total_Characters = 0;
    double Average = 0.0;
    cout << "Please enter a string of 500 or less characters: ";
    cin.getline(userString, size);
    cout << "n";
    Count_All (userString, Word, Total_Characters, Pun);
    cout << "Number of words in the string: " << Word << "n";
    Average = Calc_Average (userString, Word, Pun, Total_Characters);
    cout <<"nAverage number of letters per word: "<< fixed <<
    showpoint << setprecision(2) << Average << "n" << endl;

    cin.ignore(1);
    return 0;
}
void Count_All (char*strptr, int &Word, double &Total_Characters, int &Pun) // Counts all characters and types.
{
    int index = 0;
    while (*strptr != '')
    {
        if ((isspace(*strptr)) || (ispunct(*strptr)))
        {
            while ((isspace(*strptr)) || (ispunct(*strptr)))
            {
                index++;
            }
        }
        if ((isalnum(*strptr)) || (ispunct(*strptr)))
        {
            Word++;
            while ((isalnum(*strptr))||(ispunct(*strptr)))
            {
                index++;
                Total_Characters++; // Counting the total printable characters (including digits and punctuation).
                if((ispunct(*strptr)))
                {
                    Pun++; // Counting punctuation.
                }
            }
        }
        index++;
    }
}
double Calc_Average(char*strptr, int Word, int Pun, double Total_Characters)  // Calculates the average number of characters per words.
{
    double Average = 0.0;
    Total_Characters = Total_Characters - Pun; // Subtracting punctuation from all of the characters in the string (not including spaces).
    Average = (Total_Characters / Word);
    return Average;
}