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Topic: returning booleans from a method (Read 517 times) |
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mKoser
 
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returning booleans from a method
« on: May 23rd, 2003, 3:43pm » |
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I am struggeling with some code... it's part of a bigger project (creating some custom P5-methods for communicating with some custom-build circuit-boards... i'll post it all when the project is finished!)
When I create a method to return a boolean value, I recieve an error saying that the Method needs to return a value.
Here is my code (as simplified as I could get it):
// start of code
void setup(){
size(200, 200);
}
void loop(){
checkNum(5);
}
boolean checkNum(int num){
if(num = 5){
return true;
println("number " + num + " was passed in");
}else{
return false;
}
}
//end of code
I've gone through my Java-book and looked at java.sun.com and I just can't see what I am doing wrong!
The strange thing is, when I do something like this:
boolean sendStateBack(){
return false;
}
I get no complaints... but as soon as I place the return command within an if-statement or have the return statement return a variable (containing a boolean value) I get the error!
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mikkel crone koser | www.beyondthree.com | http://processing.beyondthree.com
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arielm
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Re: returning booleans from a method
« Reply #1 on: May 23rd, 2003, 3:59pm » |
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i think the problem is the "println()", which is placed after "return" (java, unlike javascript, don't like code placed after a "return" in the same block... and also, because your function declaration states that something is to be returned, every potential branch of code in it should always end with a "return")
not related to the current JLS error: i think you meant "num == 5" instead of "num = 5"...
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Ariel Malka | www.chronotext.org
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mKoser
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Re: returning booleans from a method
« Reply #2 on: May 23rd, 2003, 4:32pm » |
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Thank you for the quick reply, and thank you for explaining the bit about ending each branch with a return-statement 
The example I posted ealier works fine now - when applying my newly gained knowledge to some of my more advanced boolean-method tests, I am still having some trouble!
Below I have pasted some more dummy code - I am still getting an error saying the Method needs to return something.
//start code
byte[] pins = {3, 7, 21, 42, 102};
boolean[] states = {false, false, false, true, true};
int ranNum;
void setup(){
size(200, 200);
}
void loop(){
// pick a random number in array
ranNum = (int)random(5);
println("pin number : " + pins[ranNum] + " is " + getButtonState(ranNum));
delay(200);
}
boolean getButtonState(int pin){
// look through pins-array
for(int i = 0; i < pins.length; i++){
// if the passed-in number exist in the array, return it's state
if((int)inputPins[i] == pin){
return inPinStates[i];
}
}
}
//end code
A brief look at this from some of you wiz's out there (arielm?) would be greatly appriciated!
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mikkel crone koser | www.beyondthree.com | http://processing.beyondthree.com
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arielm
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Re: returning booleans from a method
« Reply #3 on: May 23rd, 2003, 4:59pm » |
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the error is still related to the "every potential branch of code" ending:
i mean the java compiler is so... that he looks into your "for" loop and says: what if the "if" is never reached? then you have a "potential" branch of code that ends without a "return"!
so one solution is to add "return false;" after the loop...
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Ariel Malka | www.chronotext.org
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