Programming Challenge 10.11 - Case Manipulator

/* Case Manipulator - This program contains three functions, upper, lower,
    and reverse.

    * The upper function accepts a pointer to a C-string as an argument.
      It steps through each character in the string, converting it to
      uppercase.

    * The lower function, too, accepts a pointer to a C-string as an
      argument. It steps through each character in the string, converting
      it to lowercase.

    * Like upper and lower, reverse accepts a pointer to a C-string. As it
      steps through the string, it tests each character to determine
      whether it is upper- or lowercase. If a character is uppercase, it
      is converted to lowercase. Likewise, if a character is lowercase,
      it is converted to uppercase.

    The functions are tested by asking for a string in function main, then
    passing it to them in the order: reverse, lower, and upper.    */

#include "Utility.h"

/* Determines character casing, changing upper- to lowercase letters
   and vice versa */
void reverse(char *);

/* Converts all characters from upper- to lowercase */
void lowercase(char *);

/* Converts all characters from lower- to uppercase */
void uppercase(char *);

int main()
{
    const int MAX_CHARS = 501;
    char         sentence[MAX_CHARS];

    cout << "\n\tCASE MANIPULATOR\n\n\t"
          << "Enter a sentence, " << (MAX_CHARS - 1)
          << " characters in length, and I will\n\t"
          << "first reverse all upper and lowercase characters, then\n\t"
          << "I will change all characters to lowercase, and lastly I\n\t"
          << "will change all characters to uppercase.\n\n";

    cout << "\n\tPlease enter your sentence:\n\t";
    cin.getline(sentence, MAX_CHARS);

    cout << "\n\n\tCHARACTER CASE REVERSAL\n";
    reverse(sentence);

    cout << "\n\tAll character cases have been reversed:\n"
          << "\t" << sentence << "\n\n";

    cout << "\n\tCHARACTERS TO LOWERCASE:\n";
    lowercase(sentence);

    cout << "\n\tAll uppercase characters have been changed "
          << "to lowercase:\n"
          << "\t" << sentence << "\n\n";
   
    cout << "\n\tCHARACTERS TO UPPERCASE:\n";
    uppercase(sentence);

    cout << "\n\tAll lowercase characters have been changed "
          << "to uppercase:\n"
          << "\t" << sentence << "\n\n";

    pauseSystem();
    return 0;
}

/* **********************************************************
   Definition: reverse

    This function accepts a pointer to a C-string as argument.
    It reverses all upercase characters to lowercase and vice
    versa.
   ********************************************************** */

void reverse(char *senPtr)
{
    for (size_t index = 0; senPtr[index] != '\0'; index++)
    {
        if (isupper(senPtr[index]))
        {
            senPtr[index] = tolower(senPtr[index]);
        }
       
        else if (islower(senPtr[index]))
        {
            senPtr[index] = toupper(senPtr[index]);
        }
    }
}

/* **********************************************************
    Definition: lowercase

    This function accepts a pointer to a C-string as argument.
    It converts all characters from upper- to lowercase.
    ********************************************************** */

void lowercase(char *senPtr)
{
    for (size_t index = 0; senPtr[index] != '\0'; index++)
    {
        if (isupper(senPtr[index]))
        {
            senPtr[index] = tolower(senPtr[index]);
        }
    }
}

/* **********************************************************
   Definition: uppercase

    This function accepts a pointer to a C-string as argument.
    It converts all characters from lower- to uppercase.
   ********************************************************** */

void uppercase(char *senPtr)
{
    for (size_t index = 0; senPtr[index] != '\0'; index++)
    {
        if (islower(senPtr[index]))
        {
            senPtr[index] = toupper(senPtr[index]);
        }
    }
}

Example Output: