Problem with menu-driven program

[t0nydanzuh]

I have a program that I have to write and can not figure out why the way I'm writing the menu isn't working. Here is my block of code for the menu so far, you can see I'm only working with 1 input so far, and I am getting an error compiling in ** ProcessPicture(input);** this line. Any help would be greatly appreciated.

public static void main(String[] args)
{
Scanner in = new Scanner (System.in);
int userChoice;
boolean quit = false;
//Picture q = p.oilPaint(5);
//q.explore();
do {
System.out.println("1. Choose a Picture to Process");
System.out.println("2. Display Picture");
System.out.println("3. Make Picture Black & White");
System.out.println("4. Make Picture Negative color");
System.out.println("5. Flip Picture 180 Degrees");
System.out.println("6. Save Picture to New File");
System.out.print("Pick a choice above or press 0 to Quit: ");
userChoice = in.nextInt();
switch (userChoice) {
case 1:
// process picture
ProcessPicture(input);
break;
case 2:
// display picture
break;
case 3:
// black and white
break;
case 4:
// negative
break;
case 5:
// flip 180 degrees
break;
case 6:
// save to new file
break;
case 0:
quit = true;
break;
default:
System.out.println("Invalid Selection, please select a choice above.");
break;
}
System.out.println();
}
while (!quit);
System.out.println("Have a nice day");
}
private void ProcessPicture(java.io.InputStream input){
Scanner in = new Scanner(input);
Picture p =
new Picture(FileChooser.pickAFile());
p.explore();
}
/*private void DisplayPicture(java.io.InputStream input)
private void BlackAndWhite(java.io.InputStream input)
private void Negative(java.io.InputStream input)
private void FlipUpsideDown(java.io.InputStream input)
private void Save(java.io.InputStream input)
*/

[Norm]

I am getting an error compiling

please copy and paste the full text of the error message here.

[t0nydanzuh]

if i put....

Scanner in = new Scanner(input);
Picture p =
new Picture(FileChooser.pickAFile());
p.explore();

into my case 1:, then it works fine. I could do this to complete the assignment but i'd rather learn how to do it correctly.

[t0nydanzuh]

the error says...

File: C:\------------\PictureMenu.java [line: 460]
Error: C:\------------\PictureMenu.java:460: cannot find symbol
symbol : variable input
location: class PictureMenu

oh and I am using DrJava if that matters

[Norm]

please copy and paste the full text of the error message here.

Your edited version leaves stuff off.

Where is the variable input defined? Is it in scope where you are trying to use it?

[t0nydanzuh]

It isn't, the last time I did a program similar to this, I had Scanner in = new Scanner (input); and it worked fine. However when I put that in, it also creates an error.

I think I'm missing something really basic, but I can't figure out what I'm doing wrong.

[Norm]

please copy and paste the full text of the error message here.

[paul pasciak]

If you use code tags, your indentations will be perserved.

I have never used case/switch statments before, except
long ago in a Pascal assignment.

All of your clues indicate to me that blocks of code within
a switch-case statement that have more than one line
of code (beyond a solitary "break;" statement), need to
have braces {} enclosing them.

Also, it is optional, but some consider it good practice to
place single lines of code, such as all of your "break;"
statements in braces {}.

EMENDED!! I'VE JUST REVEWED MANY JAVA CASE
EXAMPLES, AND I SEE I REALLY DON'T HAVE
GOOD EXPERIENCE WITH THIS TOPIC.

However, I have found an error in my indentation
of my interpretation of this code, and have corrected
it below.

  public static void main(String[] args){
    Scanner in = new Scanner (System.in);
    int userChoice;
    boolean quit = false;
    //Picture q = p.oilPaint(5);
    //q.explore();
    do {
      System.out.println("1. Choose a Picture to Process");
      System.out.println("2. Display Picture");
      System.out.println("3. Make Picture Black & White");
      System.out.println("4. Make Picture Negative color");
      System.out.println("5. Flip Picture 180 Degrees");
      System.out.println("6. Save Picture to New File");
      System.out.print("Pick a choice above or press 0 to Quit: ");
      userChoice = in.nextInt();
      switch (userChoice) {
        case 1:
          // process picture
          ProcessPicture(input);    // Probably all of this should
          break;                         // be enclosed in braces {}
        case 2:
          // display picture
          break;
        case 3:
          // black and white
          break;
        case 4:
          // negative
          break;
        case 5:
          // flip 180 degrees
          break;
        case 6:
          // save to new file
          break;
        case 0:
          quit = true;
          break;
        default:
          System.out.println("Invalid Selection, please select a choice above.");
          break;
      }
      System.out.println();
    }
    while (!quit);
    System.out.println("Have a nice day");
  }

  private void ProcessPicture(java.io.InputStream input){
    Scanner in = new Scanner(input);
    Picture p = new Picture(FileChooser.pickAFile());
    p.explore();
  }

  /*private void DisplayPicture(java.io.InputStream input)
  private void BlackAndWhite(java.io.InputStream input)
  private void Negative(java.io.InputStream input)
  private void FlipUpsideDown(java.io.InputStream input)
  private void Save(java.io.InputStream input)
  */ 
}

[t0nydanzuh]

1 error found:
File: C:\Users\Steve\Desktop\CS260\java-source\PictureMenu.java [line: 461]
Error: C:\Users\Steve\Desktop\CS260\java-source\PictureMenu.java:461: cannot find symbol
symbol : variable input
location: class PictureMenu

[Norm]

What is the source code on line 461?
Did you leave off some of the error message? When I compile with an error I get:

TestCode2.java:45: cannot find symbol
symbol: variable TRUE
         return TRUE;
                ^
1 error

Notice the source line and the ^ pointer.

[t0nydanzuh]

line 461 is:

ProcessPicture(input);

[Norm]

Where is the variable: input defined?
I think I already have asked this question in post#5.

[t0nydanzuh]

i figured it out. What happened is I had this in the main method, and it couldnt work that way. Here's my working code, thanks for the help.


Scanner in = new Scanner (System.in);
public static void main(String[] args)
{
PictureMenu p = new PictureMenu();

p.PictureMenus(System.in);
}
public void PictureMenus(java.io.InputStream input){
Scanner in = new Scanner (input);
int userChoice;
boolean quit = false;
//Picture q = p.oilPaint(5);
//q.explore();
do {
System.out.println("1. Choose a Picture to Process");
System.out.println("2. Display Picture");
System.out.println("3. Make Picture Black & White");
System.out.println("4. Make Picture Negative color");
System.out.println("5. Flip Picture 180 Degrees");
System.out.println("6. Save Picture to New File");
System.out.print("Pick a choice above or press 0 to Quit: ");
userChoice = in.nextInt();
switch (userChoice) {
case 1:
// process picture
ProcessPicture(input);
break;
case 2:
// display picture
break;
case 3:
// black and white
break;
case 4:
// negative
break;
case 5:
// flip 180 degrees
break;
case 6:
// save to new file
break;
case 0:
quit = true;
break;
default:
System.out.println("Invalid Selection, please select a choice above.");
break;
}

System.out.println();
}
while (!quit);
System.out.println("Have a nice day");
}
private void ProcessPicture(java.io.InputStream input){
Scanner in = new Scanner(input);
Picture p =
new Picture(FileChooser.pickAFile());
p.explore();
}
/*private void DisplayPicture(java.io.InputStream input)
private void BlackAndWhite(java.io.InputStream input)
private void Negative(java.io.InputStream input)
private void FlipUpsideDown(java.io.InputStream input)
private void Save(java.io.InputStream input)
*/
}

[t0nydanzuh]

Since I have your attention, do you know the best way to save a picture to a new file? with extensions such as .jpg or .gif

[Norm]

An easy way is the ImageIO class.