Thread: Program Jumps Between Cases Without Reason

  1. 12-31-2014 #1
    danlee58
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    Program Jumps Between Cases Without Reason

    This program seems to jump between cases without any reason.


    Code:
    INDEX = 1;


While(1) {

switch (INDEX){
				
case 1:				//INDEX = 1	
									
if (ABC < LOOKUP3(TPS_INDEX, OneUP, 10)){
						
INDEX = 1;		
						
HIGH(29);						
						
LOW1(20);						
						
LOW1(23);						
						
LOW1(25);						
								
					

}		//END IF
						
else {
INDEX = 2;			
						
HIGH(29);						
HIGH1(20);					
LOW1(23);							
LOW1(25);						
}	//END ELSE

break;	//END GEAR INDEX = 1
  												
 case 2:				//INDEX = 2	
  												
if (ABC >= LOOKUP3(TPS_INDEX, TwoUP, 10)){
  						
INDEX = 3;

LOW(29);						
HIGH1(20);						
LOW1(23);							
LOW1(25);						

}	//END IF
								
else {
 													
 if (ABC < LOOKUP3(TPS_INDEX, TwoDOWN, 10)){
  						
INDEX = 1;
										
HIGH(29);					
LOW1(20);						
LOW1(23);						
LOW1(25);						
}	//END IF
}	//END ELSE
break;	//END INDEX = 2
  						
case 3:				//INDEX = 3	  				 		
if (ABC >= LOOKUP3(TPS_INDEX, ThreeUP, 10)){
						   						
LOW(29);						//SS1
LOW1(20);						//SS2
LOW1(23);						//CCS	
LOW1(25);						//TCS
												
}	//END IF	
 						
else {
  				
if (ABC < LOOKUP3(TPS_INDEX, ThreeDOWN, 10)){
  						
INDEX = 2;

HIGH(29);						
HIGH1(20);						
LOW1(23);							
LOW1(25);	
					
}  //END IF
}	//END ELSE	
break;	//END INDEX = 3
  					
case 4:				//INDEX = 4	  						
if (RPM < LOOKUP3(TPS_INDEX, FourDOWN, 10)){
  						
INDEX = 3;											
LOW(29);						
HIGH1(20);								
LOW1(23);						
LOW1(25);					
}	//END IF
else	{if (ABC >= 850){
HIGH1(25);									
} //END ELSE

else  {if (ABC < 700){
LOW1(25);
																						
}}}				//END If End ELSE End Else
							// END INDEX = 4:
						}  //End Switch INDEX 					 
 

					WAIT(100);
	
	}					//End While
    Do you need the last break at the end of the case statements?
    Does the program jump to the end of the program and then follow the while loop when a break is encountered, or to the end of the case statements?
    Do I need a Default Statement?
  2. 12-31-2014 #2
    Salem
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    Perhaps if you indented it properly, you might figure something out for yourself.
    Indent style - Wikipedia, the free encyclopedia

    It's AWFUL!
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
  3. 12-31-2014 #3
    danlee58
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    Sorry, I copied it from Notepad++.

    All the indentations got messed up. Notepad++ tracks the brackets.

    I'll try to repost it with indentations.
  4. 12-31-2014 #4
    danlee58
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    I hope that this is better!

    Code:
    int INDEX = 1;


While(1) {

	switch (INDEX){
				
	case 1:				//INDEX = 1	
									
		if (ABC < LOOKUP3(TPS_INDEX, OneUP, 10)){
						
		INDEX = 1;		
						
		HIGH(29);						
						
		LOW1(20);						
						
		LOW1(23);						
						
		LOW1(25);						
								
					

	}		//END IF
						
	else {
		INDEX = 2;			
						
		HIGH(29);						
		HIGH1(20);					
		LOW1(23);							
		LOW1(25);						
	}	//END ELSE

break;	//END INDEX = 1
  												
 	case 2:				//INDEX = 2	
  												
		if (ABC >= LOOKUP3(TPS_INDEX, TwoUP, 10)){
  						
		INDEX = 3;

		LOW(29);						
		HIGH1(20);						
		LOW1(23);							
		LOW1(25);						

		}	//END IF
								
		else {
 													
 			if (ABC < LOOKUP3(TPS_INDEX, TwoDOWN, 10)){
  						
			INDEX = 1;
										
			HIGH(29);					
			LOW1(20);						
			LOW1(23);						
			LOW1(25);						
			}	//END IF
		}	//END ELSE
break;	//END INDEX = 2
  						
case 3:				//INDEX = 3	  				 		
		if (ABC >= LOOKUP3(TPS_INDEX, ThreeUP, 10)){
						   						
		LOW(29);						//SS1
		LOW1(20);						//SS2
		LOW1(23);						//CCS	
		LOW1(25);						//TCS
												
		}	//END IF	
 						
		else {
  				
			if (ABC < LOOKUP3(TPS_INDEX, ThreeDOWN, 10)){
  						
			INDEX = 2;

			HIGH(29);						
			HIGH1(20);						
			LOW1(23);							
			LOW1(25);	
					
			}  //END IF
		}	//END ELSE	
break;	//END INDEX = 3
  					
case 4:				//INDEX = 4	  						
		if (ABC < LOOKUP3(TPS_INDEX, FourDOWN, 10)){
  						
		INDEX = 3;											
		LOW(29);						
		HIGH1(20);								
		LOW1(23);						
		LOW1(25);					
		}	//END IF
		else	{if (ABC >= 850){
			HIGH1(25);									
			} //END IF

		else  {if (ABC < 700){
			LOW1(25);
																						
		}}}				//End IF End ELSE End Else
							// END INDEX = 4:
		}  //End Switch INDEX 					 
  					

					WAIT(100);
	
	}					//End While
    Last edited by danlee58; 12-31-2014 at 07:42 PM.
  5. 12-31-2014 #5
    WoodSTokk
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    Here is a clean up of your code:
    Code:
    int INDEX = 1;

while(1) {

    switch (INDEX){

        case 1:             //INDEX = 1
            if (ABC < LOOKUP3(TPS_INDEX, OneUP, 10)) {
                INDEX = 1;
                HIGH(29);
                LOW1(20);
                LOW1(23);
                LOW1(25);
            }               //END IF
            else {
                INDEX = 2;
                HIGH(29);
                HIGH1(20);
                LOW1(23);
                LOW1(25);
            }               //END ELSE
            break;          //END GEAR INDEX = 1

        case 2:             //INDEX = 2
            if (ABC >= LOOKUP3(TPS_INDEX, TwoUP, 10)) {
                INDEX = 3;
                LOW(29);
                HIGH1(20);
                LOW1(23);
                LOW1(25);
            }               //END IF
            else {
                if (ABC < LOOKUP3(TPS_INDEX, TwoDOWN, 10)) {
                    INDEX = 1;
                    HIGH(29);
                    LOW1(20);
                    LOW1(23);
                    LOW1(25);
                }           //END IF
            }               //END ELSE
            break;          //END INDEX = 2

        case 3:             //INDEX = 3
            if (ABC >= LOOKUP3(TPS_INDEX, ThreeUP, 10)) {
                LOW(29);    //SS1
                LOW1(20);   //SS2
                LOW1(23);   //CCS
                LOW1(25);   //TCS
            }               //END IF
            else {
                if (ABC < LOOKUP3(TPS_INDEX, ThreeDOWN, 10)) {
                    INDEX = 2;
                    HIGH(29);
                    HIGH1(20);
                    LOW1(23);
                    LOW1(25);
                }           //END IF
            }               //END ELSE
            break;          //END INDEX = 3

        case 4:             //INDEX = 4
            if (RPM < LOOKUP3(TPS_INDEX, FourDOWN, 10)) {
                INDEX = 3;
                LOW(29);
                HIGH1(20);
                LOW1(23);
                LOW1(25);
            }               //END IF
            else {
                if (ABC >= 850) {
                    HIGH1(25);
                }           //END IF
                else {
                    if (ABC < 700) {
                        LOW1(25);
                    }       // End IF
                }           // End ELSE
            }               // End Else
                            // END INDEX = 4

    }                       //End Switch INDEX

    WAIT(100);
}                           //End While
    No, you don't need the break statement in the last case and you don't need a default case.
    If the program achieve a break statement in a case, it will jump out of switch.
    In your case, it will fall to the line 'WAIT(100);'.
    At the end of while loop, it jump back to the begin of while loop and execute the switch again.

    I don't know what you are try to do.
    I see only a switch in an infinity loop.
    How you plan to break the while loop?
    Last edited by WoodSTokk; 12-31-2014 at 07:46 PM.
    Other have classes, we are class
  6. 12-31-2014 #6
    grumpy
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    The switch tests the variable INDEX. Particular cases change the value of INDEX. All of this is in a "while (1)" loop so, after changing value of INDEX, the switch statement will be exercised for the new value of INDEX.


    You need to learn how to copy code into forums so it is readable. Otherwise you're relying on people to give a sensible answer when given wrong information.
    Right 98% of the time, and don't care about the other 3%.

    If I seem grumpy or unhelpful in reply to you, or tell you you need to demonstrate more effort before you can expect help, it is likely you deserve it. Suck it up, Buttercup, and read this, this, and this before posting again.
  7. 12-31-2014 #7
    danlee58
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    It's an Infinite Loop. It tests TPS_INDEX against different tables, based on INDEX, and changes INDEX based on the results of the test. It's a basic Elevator program, where INDEX is the current floor, and it goes up or down based on TPS_INDEX and the proper table for the floor.

    I have a working version, but as I add IO operations, it jumps around.
  8. 12-31-2014 #8
    grumpy
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    So you've created a forum thread because your code is doing what it is supposed to do, but you don't understand what it is supposed to do.

    People here can't help you. Your code "jumps around" because that's what it is supposed to do. If you don't understand that, the only solution is to work to understand the code, and reason about what happens when you change things.
    Right 98% of the time, and don't care about the other 3%.

    If I seem grumpy or unhelpful in reply to you, or tell you you need to demonstrate more effort before you can expect help, it is likely you deserve it. Suck it up, Buttercup, and read this, this, and this before posting again.
  9. 12-31-2014 #9
    danlee58
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    It's only supposed to jump as TPS_INDEX changes, but it changes when TPS_INDEX is steady.

    I got an answer to my question. I don't need a break or default after the last case. My Switch/Case code is OK.

    My next step is to reduce the IO operations to determine when it becomes stable.
    Last edited by danlee58; 12-31-2014 at 09:52 PM.
  10. 01-01-2015 #10
    WoodSTokk
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    Ah, okay, now the things become a little bit clearer.
    In case 2 (and also in case 3), you have a if-statement in an else-statement. You can join this like:
    Code:
    …
            }               //END IF
            else if (ABC < LOOKUP3(TPS_INDEX, TwoDOWN, 10)) {
                INDEX = 1;
                HIGH(29);
                LOW1(20);
                LOW1(23);
                LOW1(25);
            }               //END ELSE IF
…
    You can shorting the else-statement in case 4.
    It make the code better readable.
    Code:
    …
            else {
                if (ABC >= 850) HIGH1(25);
                else if (ABC < 700) LOW1(25);
            }               // End Else
…
    What i miss is switching to INDEX 4.
    I suspect it goes to the if-statement in case 3.
    Code:
    …
        case 3:             //INDEX = 3
            if (ABC >= LOOKUP3(TPS_INDEX, ThreeUP, 10)) {
                INDEX = 4;
                LOW(29);    //SS1
                LOW1(20);   //SS2
                LOW1(23);   //CCS
                LOW1(25);   //TCS
            }               //END IF
…
    But this is only a guess.
    Last edited by WoodSTokk; 01-01-2015 at 04:00 AM.
    Other have classes, we are class
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