ZCW-MetricConversions-BlueJ/ConversionTool.java

public class ConversionTool {
    public static final float IN_2_CM = 2.54f;
    public static final float CM_2_IN = 1 / IN_2_CM;
    public static final float FT_2_IN = 12f;
    public static final float IN_2_FT = 1 / FT_2_IN;
    public static final float M_2_CM = 100f;
    public static final float CM_2_M = 1 / M_2_CM;
    public static final float KM_2_CM = 100000f;
    public static final float CM_2_KM = 1 / KM_2_CM;
    public static final float MI_2_IN = 63360f;
    public static final float IN_2_MI = 1 / MI_2_IN;

    public static float CentimetersToInches(float centimeters){
        float inches = 0;
        if (centimeters > 0){
            inches = centimeters * CM_2_IN;
        }
        return inches;
    }

    public static float InchesToCentimeters(float inches){
        float centimeters = 0;
        if (inches > 0){
            centimeters = inches * IN_2_CM;
        } 
        return centimeters;
    }

    public static float FeetToMeters(float feet){
        float meters = 0;
        if (feet > 0){
            meters = feet * FT_2_IN * IN_2_CM * CM_2_M;
        }
        return meters;
    }

    public static float MetersToFeet(float meters){
        float feet = 0;
        if (meters > 0){
            feet = meters * M_2_CM * CM_2_IN * IN_2_FT;
        }
        return feet;
    }

    public static float CelsiusToFahrenheit(float celsius){
        return celsius * (9f/5f) + 32f;
    }

    public static float FahrenheitToCelsius(float fahrenheit){
        return (fahrenheit - 32f) * (5f/9f);
    }

    public static float MphToKph(float mph){
        float kph = 0;
        if (mph > 0){
            kph = mph * MI_2_IN * IN_2_CM * CM_2_KM;
        }
        return kph;
    }

    public static float KphToMph(float kph){
        float mph = 0;
        if (kph > 0){
            mph = kph * KM_2_CM * CM_2_IN * IN_2_MI;
        }
        return mph;
    }
}