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Index › Programming Questions & Help › Syntax Questions › comparing a user-entered char array to a string
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comparing a user-entered char array to a string? (Read 690 times)
euphoriafish
comparing a user-entered char array to a string?
Oct 15th, 2007, 6:08pm  
Ok, so I'm not entirely new to programming but I'm new to Java and my general knowledge is all over the place.

I'm trying to create an array from key presses entered by the user, and then I want to compare the array to a string taken from a text file.  So eventually I want two arrays.  I'm confused as to how to fill a character array one key press at a time.

I tried this:

char data[]= new char[10];
int index=0;

void keyPressed()
{

while(index<10)
{
 if(key=='a')
 {
   //add 'a' to the string
   data[index]='a';  
   index++;
 }
println(data + " ");
}
}


But it doesn't work-- it inputs an infinite number of key presses but doesn't go on to output statement. Adding a while loop isn't enough?
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I'm running:&& &&Arduino v 0009 Alpha&&Processing v 0135 Beta&&Mac OSX 10.4.11
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JohnG
Re: comparing a user-entered char array to a strin
Reply #1 - Oct 15th, 2007, 10:02pm  
I'm not entirely sure what's casing the problem you're seeing, but as an aside, you can read input into a String, rather than a char[], which will save you a lot of manual work in most cases as well as giving you easy access to comparing options.
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fry
Re: comparing a user-entered char array to a strin
Reply #2 - Oct 16th, 2007, 12:51am  
do not use while(), since index++ only happens once, the while() loop will never finish, so the program can never continue (and keyPressed() will never be called again). in this case, use if().
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euphoriafish
Re: comparing a user-entered char array to a strin
Reply #3 - Oct 18th, 2007, 2:54am  
Thank you for the advice!  I'm still a bit confused though.  I'm feeling really stupid since I saw something that worked a few weeks ago but now that I need it I can't find it.

JohnG--  Yes, actually I originally wanted to enter my input as a String.  I know how to do this in C++, but I can't find a Java/Processing equivalent to "cin."  There is for entering user input to a string in just one or two lines of code, isn't there?  The examples I am seeing all assign specific programmer-determined values to the string rather than taking user input.  

fry-- Thanks.  I had a feeling using while() was a bad idea, but I guess I don't understand how the key listener works.  I don't understand how to make it stop taking input after 10 key presses.  All I have managed to do is make the array go out of bounds by leaving the while() out.
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I'm running:&& &&Arduino v 0009 Alpha&&Processing v 0135 Beta&&Mac OSX 10.4.11
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jomo
Re: comparing a user-entered char array to a strin
Reply #4 - Oct 18th, 2007, 5:27am  
Maybe something like:
Code:

String data[]= new String[10];
String test = "a";
int index=0;
void setup(){
 }
 
void draw(){
}
 
void keyPressed(){
  if(test.equals(String.valueOf(key))){
    if(index < data.length){
	data[index]="a";    
	index++;
	println(data);
    }else{
	println("array full");
    }
  }
}
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euphoriafish
Re: comparing a user-entered char array to a strin
Reply #5 - Oct 20th, 2007, 12:05am  
Jomo, thank you!  I still can't find the example I was using before, but your way works and solves my problem so I can go on to things that are more fun.  Kudos.
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I'm running:&& &&Arduino v 0009 Alpha&&Processing v 0135 Beta&&Mac OSX 10.4.11
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