Why would this code skip all the if statements before and directly run the "string blank" part?

[Emilysea]

/**

• A program to carry on conversations with a human user.
• This is the initial version that:
• • Uses indexOf to find strings
  • Handles responding to simple words and phrases
• This version uses a nested if to handle default responses.
• @author Laurie White

• @version April 2012 */ public class Magpie2 { /**

  • Get a default greeting
  • @return a greeting */ public String getGreeting() { return "Hello, let's talk."; }

  /**

  • Gives a response to a user statement
  • @param statement
  • the user statement
  • @return a response based on the rules given */ public String getResponse(String statement) { String response = ""; if (statement.indexOf("no") >= 0) { response = "Why so negative?"; } else if (statement.indexOf("mother") >= 0 || statement.indexOf("father") >= 0 || statement.indexOf("sister") >= 0 || statement.indexOf("brother") >= 0) { response = "Tell me more about your family."; } else if(statement.indexOf("dog") >= 0 || statement.indexOf("cat") >= 0) { response = "Tell me more about your pets."; } else if(statement.indexOf("Mr.") >= 0) { response = "He sounds very interesting."; } else if(statement.indexOf("Ms.") >= 0) { response = "She sounds very interesting."; } else if(statement.indexOf("day") >= 0) { response = "Tell me more about your day."; } else if(statement.indexOf("time") >= 0) { response = "Do you have a good time?"; } else if(statement.indexOf("yes") >= 0) { response = "Ha, I like your attitude."; } String blank = statement.trim(); if(blank.length() ==0) { response = "Come on say something."; } else { response = getRandomResponse(); } return response; }

  /**

  • Pick a default response to use if nothing else fits.

  • @return a non-committal string / private String getRandomResponse() { final int NUMBER_OF_RESPONSES = 6; double r = Math.random(); int whichResponse = (int)(r NUMBER_OF_RESPONSES); String response = "";

    if (whichResponse == 0) { response = "Interesting, tell me more."; } else if (whichResponse == 1) { response = "Hmmm."; } else if (whichResponse == 2) { response = "Do you really think so?"; } else if (whichResponse == 3) { response = "You don't say."; } else if (whichResponse == 4) { response = "Yeah that is fun!"; } else if (whichResponse == 5) { response = "Let me think..."; } return response; } }

[testZH0718]

  Uses indexOf to find strings
     Handles responding to simple words and phrases 
This version uses a nested if to handle default responses.

@author Laurie White

@Version April 2012
/
public class Magpie2
{
/*

Get a default greeting
@return a greeting
*/
public String getGreeting()
{
return "Hello, let's talk.";
}
/**

Gives a response to a user statement
@Param statement
       the user statement
@return a response based on the rules given
*/
public String getResponse(String statement)
{
String response = "";
if (statement.indexOf("no") >= 0)
{
response = "Why so negative?";
}
else if (statement.indexOf("mother") >= 0
|| statement.indexOf("father") >= 0
|| statement.indexOf("sister") >= 0
|| statement.indexOf("brother") >= 0)
{
response = "Tell me more about your family.";
}
else if(statement.indexOf("dog") >= 0
|| statement.indexOf("cat") >= 0)
{
response = "Tell me more about your pets.";
}
else if(statement.indexOf("Mr.") >= 0)
{
response = "He sounds very interesting.";
}
else if(statement.indexOf("Ms.") >= 0)
{
response = "She sounds very interesting.";
}
else if(statement.indexOf("day") >= 0)
{
response = "Tell me more about your day.";
}
else if(statement.indexOf("time") >= 0)
{
response = "Do you have a good time?";
}
else if(statement.indexOf("yes") >= 0)
{
response = "Ha, I like your attitude.";
}
String blank = statement.trim();
if(blank.length() ==0)
{
response = "Come on say something.";
}
else
{
response = getRandomResponse();
}
return response;
}
/**

Pick a default response to use if nothing else fits.

@return a non-committal string
*/
private String getRandomResponse()
{
final int NUMBER_OF_RESPONSES = 6;
double r = Math.random();
int whichResponse = (int)(r * NUMBER_OF_RESPONSES);
String response = "";

if (whichResponse == 0)
{
response = "Interesting, tell me more.";
}
else if (whichResponse == 1)
{
response = "Hmmm.";
}
else if (whichResponse == 2)
{
response = "Do you really think so?";
}
else if (whichResponse == 3)
{
response = "You don't say.";
}
else if (whichResponse == 4)
{
response = "Yeah that is fun!";
}
else if (whichResponse == 5)
{
response = "Let me think...";
}
return response;
}
}

[testZH0718]

if(blank.length() ==0)
{
response = "Come on say something.";
}
else
{
response = getRandomResponse();
}
return response;

see here, you re assign the value of the variable response, no matter what it was assigned before

[Emilysea]

But I also assigned value of response every single one before, why wouldn't the code run those before and run this line?

[zh3036]

because you did not print, you only assign, and you return at last

[Emilysea]

So does it mean the computer would regard the lines below "string blank" as another part , it would only print the last response?

[zh3036]

where do you think it print things?

[zh3036]

does the computer print everything you assigned to a variable or when you write system.out.print

[Emilysea]

Yea I got what you mean, when I wrote the code I wanted the "if(blank.length() ==0)" line to be identical to any "else if" before, and return the final response. But maybe it was a separate part starting from string blank.

[zh3036]

sorta... i am not sure about the "seperate part" thing, eveyrthing is connected...

[Emilysea]

else if(statement.indexOf("yes") >= 0)
{
response = "Ha, I like your attitude.";
}
String blank = statement.trim();
if(blank.length() ==0)
{
response = "Come on say something.";
}
else
{
response = getRandomResponse();
}
return response;

I mean if it was connected, why would return response return only the last one? So I guess from String blank it was another "if else"statement different from the previous one. And the return response only work on this particular "if else" statement, exclude the ones before.

[zh3036]

consider this example

a=1
a=2
a=3
a=4
return a

what do you think it will return

[Emilysea]

I think all four.

[zh3036]

what do you think return mean, how does it return all four

[zh3036]

suppose i have

Int getnumber(){
a=1
a=2
a=3
a=4
return a
}

main(){
system.out.println(getnumber);
}

you think it print 1 2 3 4 , right?

[Emilysea]

Yes, I think it returns all values ''a'' have.

[zh3036]

but , you see, the programs runs linearly, how come i print once, but print 4 numbers?

[Emilysea]

So a's value changes until a == 4 and a is 4?

[zh3036]

imagine a as a house, and the number is what is in the house. the number changes 4 times, and after forth change, the number inside the house is 4. now i return the house to someone else, and they found there is a 4 inside

[Emilysea]

Yea got it;)