truth table

[Lenny Leon]

I'm just starting out learning Java and need a little help. I'm supposed to take this truth table and alter it so it displays 1's and 0's instead of true false. I'm assumed to do this I would just need to change the variable type and replace true and false with 1 and 0 but every way I try this does not work. I would just like for someone to point me in the right direction. I would like an explanation so I could understand instead of just an awnser. Thanks in advance

  
//a truth table for the logical operators.
 
class LogicalOpTable {
 
public static void main(String args[]) {
 
  boolean p, q;
 
  System.out.println("P\tQ\tAND\tOR\tXOR\tNOT");
 
  p = true; q = true;
  System.out.print(p + "\t" + q +"\t");
  System.out.print((p&q) + "\t" + (p|q) + "\t");
  System.out.println((p^q) + "\t" + (!p));
 
  
  p = true; q = false;
  System.out.print(p + "\t" + q +"\t");
  System.out.print((p&q) + "\t" + (p|q) + "\t");
  System.out.println((p^q) + "\t" + (!p));
 

  p = false; q = true;
  System.out.print(p + "\t" + q +"\t");
  System.out.print((p&q) + "\t" + (p|q) + "\t");
  System.out.println((p^q) + "\t" + (!p));
 
  
  p = false; q = false;
  System.out.print(p + "\t" + q +"\t");
  System.out.print((p&q) + "\t" + (p|q) + "\t");
  System.out.println((p^q) + "\t" + (!p));
 
  }
 
}
 

[Liam Tiarnach]

Originally posted by Lenny Leon:
I'm just starting out learning Java and need a little help. I'm supposed to take this truth table and alter it so it displays 1's and 0's instead of true false. I'm assumed to do this I would just need to change the variable type and replace true and false with 1 and 0 but every way I try this does not work. I would just like for someone to point me in the right direction. I would like an explanation so I could understand instead of just an awnser. Thanks in advance

okay, so break down what !p means...
! = a boolean operator that inverts the value of a boolean...
So...

if p is true then !p ( NOT p ) is false, otherwise...
if p is false then !P ( NOT p ) is true... Hmmm... the opposite...

so if you use integers... then you could look at it like this...

if p is 1 then !p ( NOT p) then p is 0, else
if p is 0 then !p ( NOT p) then p is ???
... you can take it from here...

now you got some of the logic, making it work should be easier...

[Lenny Leon]

I've got it to work (though I don't think its correct) but in order for it to work I removed the ! operator. It won't compile when I leave it in. How do I fix this so it includes the ! operator?

This is the code with the NOT operator still in. It would not compile this way

  
 
class $LogicalOpTable {
 
public static void main(String args[]) {
 
  
  int p, q;
  
  
 
  System.out.println("P\tQ\tAND\tOR\tXOR\tNOT");
 
  
  p = 0; q = 0;
  System.out.print(p + "\t" + q +"\t");
  System.out.print((p&q) + "\t" + (p|q) + "\t");
  System.out.println((p^q) + "\t"+ (!p));
 
  
 
  p = 0; q = 1;
  System.out.print(p + "\t" + q +"\t");
  System.out.print((p&q) + "\t" + (p|q) + "\t");
  System.out.println((p^q) + "\t + (!p)");
 

  p = 1; q = 0; 
  System.out.print(p + "\t" + q +"\t");
  System.out.print((p&q) + "\t" + (p|q) + "\t");
  System.out.println((p^q) + "\t + (!p)");
 
  
  p = 1; q = 1;
  System.out.print(p + "\t" + q +"\t");
  System.out.print((p&q) + "\t" + (p|q) + "\t");
  System.out.println((p^q) + "\t" + (!p));
 
  }
 
}
 

[Nigel Browne]

I didn't want to do all your work for you but look at the code below and see if you can work from there.

public class LogicalOpTable {
   public static void main(String args[]) {
     boolean p, q; //notice I keep the boolean type
     System.out.println("P\tQ\tAND\tOR\tXOR\tNOT");
 
     
     //Notice the use of the Boolean operator ?:
     //Look this up in the Java Language Specification, section 16.1.5
     p = false; q = false;
     System.out.print(p? 1:0  + "\t"); 
     System.out.print(q? 1:0  +"\t");
     System.out.print((p&q)? 1:0 + "\t");
     System.out.print((p|q)? 1:0  + "\t"); 
     System.out.print((p^q)? 1:0  + "\t");
     System.out.println((!p)? 1:0);
 
     //you will need to change this section
     p = true; q = true;
     System.out.print(p + "\t" + q +"\t");
     System.out.print((p&q) + "\t" + (p|q) + "\t");
     System.out.println((p^q) + "\t"+ (!p));
     
     //you will need to change this section
     p = true; q = false;
     System.out.print(p + "\t" + q +"\t"); 
     System.out.print((p&q) + "\t" + (p|q) + "\t"); 
     System.out.println((p^q) + "\t" + (!p));
     
     //you will need to change this section
     p = false; q = true;
     System.out.print(p + "\t" + q +"\t");
     System.out.print((p&q) + "\t" + (p|q) + "\t");
     System.out.println((p^q) + "\t" + (!p));
  }
}

hope this helps

[Joel McNary]

The important lesson to learn here is that Nigel did not change the underlying code in the program...he kept the data types the same and simply changed the user interface to display 1's and 0's instead of trues and falses.

You could also then change it to display Y/N, T/F (or, for the really sadistic, A/B or even N/Y.....)

You might want to add a could of static variables:

private static final String TRUE_DISPLAY = "1";
private static final String FALSE_DISPLAY = "0";

If you were yo use these in the code, you could change the displays to whatever your heart desired with very little effort.

[Ben Don]

In order to compile, I had to adapt this code below by inserting parenthesis around the ternary operator section. For example - System.out.print((p? 1:0) + "\t"); How did you get around this?

Nigel Browne wrote:I didn't want to do all your work for you but look at the code below and see if you can work from there.

public class LogicalOpTable {
   public static void main(String args[]) {
     boolean p, q; //notice I keep the boolean type
     System.out.println("P\tQ\tAND\tOR\tXOR\tNOT");
 
     
     //Notice the use of the Boolean operator ?:
     //Look this up in the Java Language Specification, section 16.1.5
     p = false; q = false;
     System.out.print(p? 1:0  + "\t"); 
     System.out.print(q? 1:0  +"\t");
     System.out.print((p&q)? 1:0 + "\t");
     System.out.print((p|q)? 1:0  + "\t"); 
     System.out.print((p^q)? 1:0  + "\t");
     System.out.println((!p)? 1:0);
 
     //you will need to change this section
     p = true; q = true;
     System.out.print(p + "\t" + q +"\t");
     System.out.print((p&q) + "\t" + (p|q) + "\t");
     System.out.println((p^q) + "\t"+ (!p));
     
     //you will need to change this section
     p = true; q = false;
     System.out.print(p + "\t" + q +"\t"); 
     System.out.print((p&q) + "\t" + (p|q) + "\t"); 
     System.out.println((p^q) + "\t" + (!p));
     
     //you will need to change this section
     p = false; q = true;
     System.out.print(p + "\t" + q +"\t");
     System.out.print((p&q) + "\t" + (p|q) + "\t");
     System.out.println((p^q) + "\t" + (!p));
  }
}

hope this helps

[Campbell Ritchie]

Welcome to the Ranch

You have a + operator in that line, which has a higher precedence than ?:. So without the () you would offer it the choice between printing 1 and printing "0\t"; those are incompatible types (int and String), so the compiler wouldn't be happy.
What about using % tags
System.out.printf("%d\t", p ? 1 : 0);

[fred rosenberger]

You guys realize this thread is nine years old, right?

[Ben Don]

Yes, but the answer didn't work as written. The problem hasn't changed.

[Campbell Ritchie]

Please explain what you expect to happen and what is actually happening.