Java Basics 113– Logic Errors
STEPS
1) CREATE NEW PROJECT
Project Name: errorhandling2
Main Class Name: errorhandling.errorChecking2
Delete all comments and unnecessary codes, leaving only the following codes.
package errorhandling2;
public class errorChecking2 {
public static void main(String[] args) {
// TODO code application logic here
}
}
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2) Edit codes.
2-1) Insert the codes for main method as follows.
package errorhandling2;
public class errorChecking2 {
public static void main(String[] args) {
int LetterCount = 0;
String check_word = "Debugging";
String single_letter = "";
int i;
for (i = 0; i < check_word.length(); i++) {
single_letter = check_word.substring(1, 1);
if (single_letter.equals("g")) {
LetterCount++;
}
}
System.out.println("G was found " + LetterCount + " times.");
}
}
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2-2) Run.
Problem: The word “Debugging” contains two “g”s but the program outputs that “G was found 0 times.”
3) Add Break Point.
3-1) Click the left margin of the code editor window to mark the Break Point.
3-2) Go to menu bar, select Debug/Debug Project.
3-3) Click Step Into button.
3-4) Watch the change in the value of variables.
3-5) Stop the debugging.
3-6) Edit your codes as follows.
package errorhandling2;
public class errorChecking2 {
public static void main(String[] args) {
int LetterCount = 0;
String check_word = "Debugging";
String single_letter = "";
int i;
for (i = 0; i < check_word.length(); i++) {
single_letter = check_word.substring(i, i+1);
if (single_letter.equals("g")) {
LetterCount++;
}
}
System.out.println("G was found " + LetterCount + " times.");
}
}
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3-7) Observe the Variables in Debug Window.
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