function in C++

Question

When a function is finished, closed bracket}, where does the programming go?

My programming seems to fall through, that is the next function after the current function is complete seems to be running. Are incorrect brackets causing my problem?

For example:

void loop() ;

{

do my first thing;

if test 1 true, go to void thing2

if test 2 true, go to void thing3

}

Where am I at this point? Am I back in the loop or do I fall through thing3 to what is after it in the program.

Please straighten me out a little. I am new to C++.

Thanks

Bill

gadget.iom · Accepted Answer

Hi billpenner

The loop function will repeat indefinitely.

The go-to parts of your code could transfer the program flow to the associated labels, from which the code will continue, essentially skipping any code in

between.

eg:

for(byte r = 0; r < 255; r++){
  for(byte g = 255; g > -1; g--){
  for(byte b = 0; b < 255; b++){
  if (analogRead(0) > 250){ goto bailout;}
  // more statements ...
  }
  }
}
bailout:

A better approach may be to turn the goto's into function calls. in this case the program flow will move to the function you declared and then return back to the point immediately after the function call.

eg.

void setup(){
  Serial.begin(9600);
}

void loop() {
  int i = 2;
  int j = 3;
  int k;

  k = myMultiplyFunction(i, j); // k now contains 6
  Serial.println(k);
  delay(500);
}

int myMultiplyFunction(int x, int y){
  int result;
  result = x * y;
  return result;
}

More information can be found on the following pages:

Arduino - Goto

Arduino - FunctionDeclaration

Does this clarify the situation somewhat?

Paul

Robert Peter Oakes · Answer

OK, Call out the censors, he used the GOTO word…….. Ok, more seriously, GOTO is a bad thing to use and can leave you with a mess from a memory and cpu resource perspective, most modern languages do not even have it The loop function technically does not loop forever as it is a simple function call, the underlying runtime is where the loop really is and it calls the loop function repeatedly This is an important distinction as any variables you initialize in this function will be initialized again and again if your not careful and therefor mess with your program or just simply waste resources If you want to be able to break out of a loop, set a variable to help and then use it as part of the looping condition, when your ready to exit, set the variable to the condition that cause the loop to exit The LOOP() function is not the loop, remember that This is a forever loop While (true == true) { //Do stuff } Changing this to Boolean exitFlag = false; While (exitFlag == false) { //Do stuff and at some point set exitFlag to true) } This is the same basic loop but now has the ability to exit under proper control without a goto statement

coolbox · Answer

hi, your problem seems simple.can you just give more actual code. But an intermediate answer: if void loop() is actually while(1) of for( ; ; ) then "first thing " will always happen irrespective of any thing(any result or condition). but thing2 and thing3 will depend on their condition. 
 billpenner wrote: 
 
 When a function is finished, closed bracket}, where does the programming go? 
 My programming seems to fall through, that is the next function after the current function is complete seems to be running. Are incorrect brackets causing my problem? 
 For example: 
 void loop() ; 
 { 
 do my first thing; 
 if test 1 true, go to void thing2 
 if test 2 true, go to void thing3 
 } 
 Where am I at this point? Am I back in the loop or do I fall through thing3 to what is after it in the program. 
 Please straighten me out a little. I am new to C++. 
 Thanks 
 Bill

Okay where are you after " } " ? if you can really reach at } then you will be sure at "first thing" . But the thing that you really reach at "}" depends on code above "}".ie first thing ,thing2 ,thing3. Regards, Parth

function in C++

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