ANSWERS TO STRING PROCESSING PROBLEMS

// Problem 1.
public static void main(String[] args)
{
    String s, upperS;
    int i, vowelCount = 0;
    char x;

    s = JOptionPane.showMessageDialog("Enter a string.");
    upperS = s.toUpperCase();
    for(i = 0; i < s.length(); i++)
    {
        x = upperS.charAt(i);
        if(x=='A' || x=='E' || x=='I' || x=='O' || x=='U') 
            vowelCount++;
    }
    System.out.println("The number of vowels in " + s + " is " +
        vowelCount + ".");
}

// Problem 2.
public static void main(String[] args)
{
    String s;
    int i, upperCaseCount = 0;
    char x;

    s = JOptionPane.showMessageDialog("Enter a string.");
    for(i = 0; i < s.length(); i++)
    {
        x = s.charAt(i);
        if('A' <= x && x <= 'Z') 
            upperCaseCount++;
    }
    System.out.println("The number of upper case letters " +
        s + " is " + upperCaseCount + ".");
}

// Problem 3.
public static void main(String[] args)
{
    String s;
    int i; 
    char x;
    boolean flag = false;

    s = JOptionPane.showMessageDialog("Enter a string.");
    for(i = 0; i < s.length(); i++)
    {
        x = s.charAt(i);
        if('0' <= x && x <= '9') 
            flag = true;
    }
    System.out.println(flag);
}

// Problem 4.
public static void main(String[] args)
{
    String s;
    int i; 
    char x;
    boolean flag = true;

    s = JOptionPane.showMessageDialog("Enter a string.");
    for(i = 0; i < s.length(); i++)
    {
        x = s.charAt(i);
        if(x != '*') 
            flag = false;
    }
    System.out.println(flag);
}

// Problem 5.
public static void main(String[] args)
{
    String s;
    int i; 
    char x;
    boolean flag = false;

    s = JOptionPane.showMessageDialog("Enter a string.");
    for(i = 0; i < s.length(); i++)
    {
        x = s.charAt(i);
        if(x == 'x') 
            flag = true;
    }
    System.out.println(flag);
}

// Problem 6.
public static void main(String[] args)
{
    String s;
    char x;
    boolean flag = false;

    s = JOptionPane.showMessageDialog("Enter a string.");
    if (s.length() == 0)
        System.out.println(
             "Length of string is 0.");
    else if(s.charAt(0) == s.charAt(s.length() - 1))
        System.out.println(
             "String begins and ends with same letter.");
    else
        System.out.println(
             "String does not begin and end with same letter.");
}