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Thread: Class Temperature, not sure about constructor/methods

  1. #1
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    Question Class Temperature, not sure about constructor/methods

    For my class I need 4 constructors, one for every object variable (set value to 0 and unit to Celsius), one with 2 parameters for the 2 objectvariables and one without arguments, whereas 0 degreeC is initialized. I think I have the constructors right.

    But I am not sure if my methods are right. I need to return Temperature (C and F); set Value, Unit or both; and return the Temperature in String. I've tried this and I think I am right but not too sure, may someone check?

    [CODE = Java]
    // object variables
    	float Value;
    	char Unit;
     
    // constructors	
    	Temp(float Value){	
    		this.Value = Value;
    		Value = 0;
    	}
     
    	Temp(char Unit){
    		this.Unit = Unit;
    		Unit = 0;
    	}
     
    	Temp (float Value, char Unit) {
    		this.Value = Value; this.Unit = Unit;
    	}
     
    	Temp () {	Value = 0; Unit = 'C'; }
     
    //now the methods:
     
            float getCelsius (float Value) {
    		float Celsius;
    		Celsius = Value;
    		return Celsius; 
    	}
     
    	float getFahrenheit (float Value) {
    		float Pre;
    		float Fahrenheit;
     
    		Pre = (9*Value/5)+32;
    		Fahrenheit = Math.round(Pre*10f)/10f;
    		return Fahrenheit;
    	}
     
    	void setValue (float V) {
    		Value = V;
    	}
     
    	void setUnit (char U) {
    		Unit = U;
    	}
     
    	void setBoth (float V, char U) {
    		Value = V;
    		Unit = U;
    	}
     
    	String tempToString (float Celsius, float Fahrenheit) {
    		String c = Float.toString(Celsius);
    		String f = Float.toString(Fahrenheit);
     
    		return c + f;
    	}
    Last edited by hiro; May 23rd, 2020 at 06:50 PM.

  2. #2
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    Default Re: Class Temperature, not sure about constructor/methods

    I think I am right but not too sure
    What concerns do you have? Is the program's output OK?

    One problem I see in the code is the naming of variables. Variable names should start with lowercase letters.

    variables can be declared and given a value in one statement on a single line. No need to have two statements and lines:
    float cel = value * 13.3;

    What is in the variable named Value? The variable name should describe what the variable contains.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Class Temperature, not sure about constructor/methods

    For example, one part task is: three methods that set value, unit (C or F) or value and unit
    My code would be:

     
    void setValue (float V) {
    		Value = V;
    	}
     
    	void setUnit (char U) {
    		Unit = U;
    	}
     
    	void setBoth (float V, char U) {
    		Value = V;
    		Unit = U;
    	}

    and I am not sure what exactly is "set" and if this is the right way. First time I use methods/constructor

    --- Update ---

    Value would be Celsius. (C or F according to task)

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    Default Re: Class Temperature, not sure about constructor/methods

    I am not sure what exactly is "set"
    That is very important to know before trying to write any code.

    What is in the variable: Value (it should be value)? Is it the temperature in degrees? Then a better name might be numberOfDegrees.
    setValue should be named setDegrees
    The contents of unit then says whether the degrees are Fahrenheit or Celsius
    The get methods would need to look at unit to know what value was in numberOfDegrees to know whether or not it needed to be converted.
    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Class Temperature, not sure about constructor/methods

    If you don't understand my answer, don't ignore it, ask a question.

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    Default Re: Class Temperature, not sure about constructor/methods

    'get' methods don't usually take an argument unless it's necessary to calculate or select the value to return. They certainly shouldn't take an argument with the same name as a class member variable - that's just asking for confusion, and the results may not be what you want - for example, your 'getCelsius' method will just return the same value you pass to it because the argument name hides the class variable with the same name and gets used instead.

    You should work out how you want the class to work before writing any code. For example, if someone calls setValue(...) to put a temperature value into the object, they will probably expect to get that value back when they call getValue().

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