Question

I am teaching myself C# and one of the current chapters challenges asks me to prompt the user for a string, write back the string, count the number of characters, the instances of the letter ‘e’ and finally the instances of all vowels. It gave a hint to use switch but I couldn’t figure out how to do it. I did get it to work by doing it manually, but I don’t think that’s the point. 🙂 How could I use a switch statement to reduce the number of typed lines?

Console.WriteLine("Please type a sentence and hit enter: ");

string myString = Console.ReadLine();

int letterCount = myString.Split('e').Length - 1;

Console.Clear();
Console.WriteLine("Thank you.  The sentence you entered was: \n\"{0}\"", myString);
Console.WriteLine("This sentence is {0} characters long.", myString.Length);
Console.WriteLine("It contains {0} instances of the letter \'e\'.", letterCount);

int vowelCount = 0;
int letterALower = myString.Split('a').Length - 1;
vowelCount += letterALower;

int letterELower = myString.Split('e').Length - 1;
vowelCount += letterELower;

int letterILower = myString.Split('i').Length - 1;
vowelCount += letterILower;

int letterOLower = myString.Split('o').Length - 1;
vowelCount += letterOLower;

int letterULower = myString.Split('u').Length - 1;
vowelCount += letterULower;

int letterAUpper = myString.Split('A').Length - 1;
vowelCount += letterAUpper;

int letterEUpper = myString.Split('E').Length - 1;
vowelCount += letterEUpper;

int letterIUpper = myString.Split('I').Length - 1;
vowelCount += letterIUpper;

int letterOUpper = myString.Split('O').Length - 1;
vowelCount += letterOUpper;

int letterUUpper = myString.Split('U').Length - 1;
vowelCount += letterUUpper;

Console.WriteLine("There are {0} vowels used.", vowelCount);
Console.ReadLine();

Answer 1

Here’s a simple solution:

string str = Console.ReadLine();
string low_str = str.ToLower();
Console.Clear();
Console.WriteLine("Thank you.  The sentence you entered was: \n\"{0}\"", str);
Console.WriteLine("This sentence is {0} characters long.", str.Length);

int vowelCount = 0;
int eCount = 0;

for (int i = 0; i < low_str.Length; i++)
{
    switch(low_str[i])
    {
        case 'e': eCount ++; vowelCount++; break;
        case 'a': vowelCount++; break;
        case 'o': vowelCount++; break;
        case 'i': vowelCount++; break;
        case 'u': vowelCount++; break;
        case 'y': vowelCount++; break;
    }
}

Console.WriteLine("It contains {0} instances of the letter \'e\'.", eCount);
Console.WriteLine("There are {0} vowels used.", vowelCount);
Console.ReadLine();

Notice that this could be done in an even fewer lines using this method (not the best way, but let’s not go too deep into the framework details 🙂 ):

int eCount = low_str.split(new char[]{'e'}) - 1;
int vowelCount = low_str.split(new char[]{'a','e','o','i','u','y'}) - 1;