COSC 135B Questions on Characters and String methods
Tom Linton, Fall 2000, Central College

1. For each code fragment below, what would be printed in the messageBox?
1. String myName = "Tom Linton";

messageBox( myName.charAt(1) );
 
 
 
 
 
2. String myName = "Tom Linton";

char aSpace = ' ';
messageBox("Your first name has " + myName.indexOf(aSpace) + " letters.");
 
 
 
3. public boolean isVowel(char aLetter){

   boolean answer = false;
   switch(aLetter){
      case 'a': case 'e': case 'i': case 'o': case 'u': case 'y':
      case 'A': case 'E': case 'I': case 'O': case 'U': case 'Y':
         answer = true;
         break;
   }
   return answer;
}
int numVowels = 0;
String myName = "Tommy Linton";
for (int letter = 0; letter < myName.length(); letter++) {
   if ( isVowel( myName.charAt(letter) ) )
      numVowels++;
}
messageBox("The String " + myName + " has " + numVowels + " vowels.");
 
 
 
 
 
 
4. String s1 = "Tom";

String s2 = "tom";
String s3 = s2.toUpperCase();
messageBox("" + s1.equals(s3) + ", " + s1.equalsIgnoreCase(s3) +
      ", " + s2.length() == s3.length() + ", " + Character.isDigit( s1.charAt(1) ) );
 
 
 
 
 
2. Write a method named charToUpper, which takes two inputs, a String, say s1 and an int, say n, and returns the String obtained by changing the character at location n in s1 to uppercase. For example, charToUpper("tom", 0) = "Tom" and charToUpper("OOPS",2) = "OOPS". HINT: You might just "add" 'A' - 'a' to some character.

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

3. How do you create a String that is the String version of an int variable? For example, if years = 125 is an int variable, how do I get a String version of years (namely, the digit 1 followed by the digit 2 followed by the digit 5)?