How do I throw an exception when I receive a signal?

Java beginner, Illegal Argument Exception?

• public class DailyWeatherData { private int dayOfMonth; private int maxTemperature; private int minTemperature; private int precipitation; public DailyWeatherData(int day, int max, int min, int precip){ day = dayOfMonth; max = maxTemperature; min = minTemperature; precip = precipitation; this.setDayOfMonth(day); this.setMaxTemperature(max); this.setMinTemperature(min); this.setPrecipitation(precip); } public void setDayOfMonth(int day){ if(day < 1 || day > 31){ throw new IllegalArgumentException("Day must be between 1 and 31, inclusive"); } else{ this.dayOfMonth = day; } } public void setMaxTemperature(int max){ if(max < -50 || max > 120){ throw new IllegalArgumentException("Max must be between -50 and 120, inclusive"); } else{ this.maxTemperature = max; } } public void setMinTemperature(int min){ if(min < -50 || min > 120){ throw new IllegalArgumentException("Min must be between -50 and 120, inclusive"); } else{ this.minTemperature = min; } } public void setPrecipitation(int precip){ if(precip < 0){ throw new IllegalArgumentException("Precip does not allow negative values"); } else{ this.precipitation = precip; } } public int getDayOfMonth(){ return dayOfMonth; } public int getMaxTemperature(){ return maxTemperature; } public int getMinTemperature(){ return minTemperature; } public double getPrecipitaion(){ return precipitation/100; } public double getAverageTemperature(){ return (maxTemperature + minTemperature)/2; } public String toString(){ String s = dayOfMonth+" , "+maxTemperature+" , "+minTemperature+" , "+(maxTemperature + minTemperature)/2+" , "+precipitation; return s; } } When entering a valid int for the 'day' parameter, it always throws the illegal argument exception.

• Answer:

  This is actually a pretty simple fix. When using the = operator, always remember that a computer reads things from right to left, and assigns values right to left. so the line: day = dayofMonth; and the following lines after it are wrong, and should really be dayofMonth = day; That first line is wrong because you are assigning an uninitialized variable to a variable that doesn't exist in the scope of your class. dayofMonth=day; This is the right way to write it, because in all comp languages, your assigning the variable on the right to the variable on the left. So just switch all of those and you should be good to go. shoot me an email at [email protected] if something else goes screwy.