CODEWITHSUNDEEP
java
Leo
Leo

Reputation: 495

java if else statement

I am a new student who is trying to use java if else statements at the moment.

I have attched my class and i need to say if this code get 0 errors for all 4 errors(error11, error12, error13 and error14), need to display the text "Answer". This code was working without the if else statements and there are 2 errors in those 2 lines. Please explain me how to do it?

public static void deltaR()
 {
 int x;  
 int x11, x12, x13, x14;
 int x21, x22, x23, x24; //inputs

 double w10, w11, w12;//weights for first neuron
 int d11, d12, d13, d14;//desired output for first neuron
 double net11, net12, net13, net14;//sum of weights times inputs
 int y11, y12, y13, y14;//outputs
 int error11, error12, error13, error14;//error

 //double w20, w21, w22;//weights for second neuron
 //int d21, d22, d23, d24;//desired output for second neuron
 //double net21, net22, net23, net24;//sum of weights times input
 //int y21, y22, y23, y24;//outputs
 //int error21, error22, error23, error24;//error

 if (error11 = 0, error12 = 0, error13 = 0, error14 = 0)
 {
  System.out.println("Answer");
 }
 else if (error11 != 0, error12 != 0, error13 != 0, error14 != 0)
 {
 double coe=0.5;//learning coefficient
 x=1;

 x11=0;
 x12=0;
 x13=1;
 x14=1;

 x21=0;
 x22=1;
 x23=0;
 x24=1;

 d11= 0;
 d12= 1;
 d13= 0;
 d14= 1;

 w10=0.5;
 w11=-1;
 w12=1.5;

 net11=(x*w10 + x11*w11 + x21*w12);
 net12=(x*w10 + x12*w11 + x22*w12);
 net13=(x*w10 + x13*w11 + x23*w12);
 net14=(x*w10 + x14*w11 + x24*w12);

 if (net11>=0)
  y11=1;
 else
  y11=0;

 if (net12>=0) 
  y12=1;
 else
  y12=0;

 if (net13>=0)
  y13=1;
 else
  y13=0;

 if (net14>=0) 
  y14=1;
 else
  y14=0;

 error11=(d11-y11);
 error12=(d12-y12);
 error13=(d13-y13);
 error14=(d14-y14);

 System.out.println("net value 1:  "+net11);
 System.out.println("net value 2:  "+net12);
 System.out.println("net value 3:  "+net13);
 System.out.println("net value 4:  "+net14);

 System.out.println("output 1:  "+y11);
 System.out.println("output 2:  "+y12);
 System.out.println("output 3:  "+y13);
 System.out.println("output 4:  "+y14);

 System.out.println("error1:  "+error11);
 System.out.println("error2:  "+error12);
 System.out.println("error3:  "+error13);
 System.out.println("error4:  "+error14);
 }
 }
}

Upvotes: 1

Views: 1097

Answers (6)

amateurs
amateurs

Reputation: 123

learn about logical operation.. they are OR (||) AND (&&) EQUAL TO (==) and NOT (!)

Upvotes: 0

Peter Lawrey
Peter Lawrey

Reputation: 533492

For mathematical comparisons you can use the following.

if (error11 == 0 && error12 == 0 && error13 == 0 && error14 == 0)

can be replaced with the following assuming errorXX is 0 or 1.

if (error11 + error12 + error13 + error14 == 0)

and

if (error11 == 0 || error12 == 0 || error13 == 0 || error14 == 0)

becomes

if (error11 * error12 * error13 * error14 == 0)

However, instead of using an int for true/false you should use a boolean. Thats what its for. e.g.

if (!(error11 || error12 || error13 || error14))

You can simplify the code so.

d11= 0;
net11=(x*w10 + x11*w11 + x21*w12);
if (net11>=0)
  y11=1;
else
  y11=0;

error11=(d11-y11);
System.out.println("error1:  "+error11);

becomes

double net11=(x*w10 + x11*w11 + x21*w12);
System.out.println("error1:  "+ (net11 >=0 ? -1 : 0));

Upvotes: 1

Carl
Carl

Reputation: 7544

The easiest way to test for what it seems you want to test is:

if ((error11 | error 12 | error13 | error 14) == 0) { //all are zero
//...do stuff
} else if ((error11 & error12 & error13 & error14) != 0) { //all are not zero
//...do different stuff
}

this makes use of the integer bitwise operations.

However, your code seems to be missing the case for some errors are zero, some are not - or at least, that case does nothing. If that case shouldn't be nothing, either add it's behavior with an else on the end or join it into one of the other cases by writing that case as an else instead of as an if test.

Upvotes: 0

Oded
Oded

Reputation: 498972

You can't use commas like that - you need to use boolean logical operators.

If you want or, use ||, if you want and use &&:

// If ANY of the error variables are 0 the if clause will execute
if(error11 == 0 || error12 == 0 || error13 == 0 || error14 == 0)

// If ALL of the error variables are 0 the if clause will execute
if(error11 == 0 && error12 == 0 && error13 == 0 && error14 == 0)

You are also using the assignment operator = instead of the equality operator ==. You should read up on your operators.

Additionally, if you always want the else clause to run when the if clause is incorrect, you do not need to add the second if conditional:

if(error11 == 0 || error12 == 0 || error13 == 0 || error14 == 0)
{
}
else
{
   // Code here will run if the above `if` clause evaluates to false
}

Not related to your question, but as a matter of style, naming your variables x, y, d and w (with the numbers or without) is bad practice - use more descriptive names and readability will increase.

Having numbers for related variables suggests that you should be using arrays. 

int[] inputs = new int[9]; // inputs is an array of 9 integers

Upvotes: 3

Yuval Adam
Yuval Adam

Reputation: 165232

When checking multiple conditions, you need to specify if it's an AND condition (&&) or an OR condition (||).

|| will stop evaluating the boolean expression once it encounters a true expression, and return true, or return false otherwise. For example:

if (userIsMale || userIsFemale) { /* user is male OR female */ }

&& will stop evaluating the boolean expression once it encounters a false expression, and return false, or return true otherwise. For example:

if (userIsHuman && userIsMale) { /* user is human AND is male */ }

Upvotes: 1

Petar Minchev
Petar Minchev

Reputation: 47373

Using commas in if statements is impossible. You must use logical operators: && which means and, and || which means or.

Upvotes: 0

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