2009年9月30日 · Are you reading the input from the keyboard, a file, or what? If you just want to check if a String is a valid double, try parsing it. If it parses, yeah! If not, an exception is thrown, …

2013年3月16日 · Hello! I'm having a lot of issues with my roman calculator. My first issue is that; Java Code: char getOperator () { System.out.println ("Enter