Odd Error: Parenthesis

RoboDesigners · Sat Dec 29, 2012 2:26 pm

I was reviewing my code from last year's competition robot, and noticed that it is now throwing an error with this expression:


	Code: cumulativeError = (cumulativeError * (1 / 6)) + error;


	Quote: Error:expression 'cumulativeError' is not constant

I was confused by this, as it was not throwing an error in April when I last opened the file.

I tried re-writing the line, and found that removing the parenthesis makes the error go away:


	Code: cumulativeError = cumulativeError * 1 / 6 + error;

Is this a bug in ROBOTC, or is it just something obvious I am overlooking?

Below is the task this line was contained in. I have also attached the entire file (lines 106 and 107 are where the issue is).


	Code: /** This task controls the arm up/down motion, listening for commands / task armControl(){ //Is the arm under computer control? bool compControl = true; int cumulativeError = 0; while(true){ //Update arm target if (vexRT[Btn7U] == 1) armTargetLevel = 3; else if(vexRT[Btn7R] == 1) armTargetLevel = 2; else if(vexRT[Btn7L] == 1) armTargetLevel = 1; else if(vexRT[Btn7D] == 1) armTargetLevel = 0; //Power arm if (compControl){ int error = ARM_POS[armTargetLevel] - SensorValue[armPot]; cumulativeError = (cumulativeError (1 / 6)) + error; int power = -(error * 0.09 + cumulativeError * 0.052); if (abs(power) > ARM_MAX_POW) power = ARM_MAX_POW * abs(power) / power; driveArm(power); } else{ driveArm(vexRT[Ch3]); //Human control cumulativeError = 0; } //Ch3 joystick stops auto-arm control, pressing a button re-initiates it if(vexRT[Ch3] > 10 \|\| vexRT[Ch3] < -10) compControl = false; if((vexRT[Btn7D] == 1) \|\| (vexRT[Btn7U] == 1) \|\| (vexRT[Btn7R] == 1) \|\| (vexRT[Btn7L] == 1)) compControl = true; wait1Msec(10); //Multi-threading wait } }

See line 106 and 107 in the attached file.

Odd Error: Parenthesis

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