Java: Flow of Control

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If statement

The statement inside of an if must return a boolean value meaning true or false. (Note: C/C++ can return an integer). Otherwise, it is the same as in C/C++ (if, then, else if, else) Example:

if(count < 0)
 { System.out.println("Error!"); }
else if (count > 10)
 { System.out.println("Stop being a hog!");
   count = 0;  /*take that*/ }
else
 { System.out.println("Great Running!");
   count++; }

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? operator

This conditional operator can also be used. This is the general formula:

test ? true_result_return : false_result_return

Here is an example:

int minimum = x < y ? x : y;

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Switch

This is the same as in C/C++. Here is an example:

switch (option) {
   case 0:
      System.out.println("You choose Thresholding");
      Threshold();  /*call the treshold method of this class*/
      break;
   case 1:
      System.out.println("You choose Bit-Slicing");
      BitSlice();  /*call the Bit-slice method of this class*/
      break;
   default:
      System.out.println("Invalid Choice!");
      break;
}

//Threshold() and BitSlice() methods defined below....

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For loop

Same as in C/C++
Exercise

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While loop

Same as in C/C++ except must have boolean test. Can break out of loops with break; statement and skip a loop with the continue; statements.

while (boolean test)
{ statements... }

Exercise

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Do loop

Same as in C/C++ except must have boolean test. Can break out of loops with break; statement and skip a loop with the continue; statements.

do {
  statements.....
} while (boolean test)
 

Labeled Loops

 
 break label;
 
 continue label; 
 
  return expression;
 
  label: statement; 

Here is an example,

loop: while (true) {   //This is an infinite loop!
    switch(option = in.read()) {   //reads in a character
       case 0:
          Threshold(); //call treshold method
          break;
       case 1:
          BitSlice(); //call bitslice method
          break;
       default:
          System.out.println("Invalid Option!");
          break loop;  // jumps out of while-loop
    }
   
    System.out.println("Type in option choice");
}