Iterating through a char array can all be a bit daunting at first. Having started coding with Python, I was use to flexible string variables that did a lot of work on their own. C++ gives the programmer more direct control over character arrays, or strings.

This program focuses on iterating a char array with a for loop. Char are simple, a single character variable. Strings are char arrays. Being arrays, strings are easy to iterate through.

The program below demonstrates how to iterate through a char array. I use pointers to create the char variables, which point to char arrays. Then the char pointers are passed as arguments to functions that iterate over the char array.

Storing and accessing strings isn’t as intuitive as I wish, but it is most defiantly required basic knowledge.

[code language=”cpp”] /*
– Write a function that receives a string as an argument. The function should
count the number of vowels in the string and return that number.
– Write another function that receives a string as an argument. The function
should count the number of consonants in the string and return that number.
*/

#include
//Required for funcations that take any c-strings as arguments
#include <iostream>
#include
using namespace std;

/*Declare functions for counting number of vowels and consonants
– Use a pointer for the char, denoted by the asterisk
– Many different representations of pointers to strings, such as:
– string literal "Hello all!"
– pointer to a character, char *pnt
– array of characters, char myString[10] */
int vowelCount(char *str);
int consonantCount(char *str);

//Start main
int main() {
//Declare required variables
const int LENGTH = 100;
char choice = ‘0’;
char line[LENGTH];
//Output need information
cout << "This program counts the number of vowels (a,e, i, o, u) and the "
<< "number of consonants appearing in a string.\n" << endl;
//Ask user to input a string
cout << "Enter a string: ";
//getline will take all text inputtted, cin stops at spaces
cin.getline(line, LENGTH);
//Ask user what function they want to run
cout << "\nA) Count the vowels in the string.\n"
<< "B) Count the consonants in the string.\n"
<< "C) Exit.\n\n";
cin >> choice;
//Use a while loop to check if the user wishes to continue to run the program
while (choice != ‘c’ && choice != ‘C’)
{
if (choice == ‘a’ || choice == ‘A’)
{
//Call the function needed to count the vowels
cout << "The string has " << vowelCount(line) << " vowels.\n" << endl;
}else if (choice == ‘b’ || choice == ‘B’)
{
//Call the function needed to count consonants
cout << "The string has "<< consonantCount(line)<< " consonants, not counting the period.\n" << endl;
}
cout << "A) Count the vowels in the string.\n"
<< "B) Count the consonants in the string.\n"
<< "C) Exit.\n\n";
cin >> choice;
}
cout << "Program terminated";
cout << "\n\n\n";
system("pause");
return 0;
}
//Declare the vowel function, use for loop to compare each char in the array
int vowelCount(char *str)
{
int count = 0;
for (int i = 0; str[i] != ‘\0’; i++)
{
// tolower converts a letter to lowercase
str[i] = tolower(str[i]);
/* – The pointer to char, str, the parameter, is used as an array of
a char to iterate through each character
– Also an array name can be used as a pointer to a char */
if (str[i] == ‘a’ || str[i] == ‘e’ || str[i] == ‘i’ || str[i] == ‘o’ ||
str[i] == ‘u’)
{
count++;
}
}
return count;
}

//Declare the consonant function, use for loop to compare each char in the array
int consonantCount(char *str)
{
int count = 0;
for (int i = 0; str[i] != ‘\0’; i++)
{
/*The pointer to char, str, is my parameter, I then use the c-string as
an array and iterate through each character to count the vowels */
str[i] = tolower(str[i]);
if (str[i] == ‘b’ || str[i] == ‘c’ || str[i] == ‘d’ || str[i] == ‘f’ ||
str[i] == ‘g’ || str[i] == ‘h’ || str[i] == ‘j’ || str[i] == ‘k’ ||
str[i] == ‘l’ || str[i] == ‘m’ || str[i] == ‘n’ || str[i] == ‘p’ ||
str[i] == ‘q’ || str[i] == ‘r’ || str[i] == ‘s’ || str[i] == ‘t’ ||
str[i] == ‘v’ || str[i] == ‘w’ || str[i] == ‘x’ || str[i] == ‘y’ ||
str[i] == ‘z’)
{
count++;
}
}
return count;
}

[/code]