小编use*_*506的帖子

使用此字符串:

String test = "hey\nyo\nsup\nyello";

我打电话给

System.out.println(test.indexOf("yello")); 

我得到11,这个数字是如何产生的？并且"\n"是否算作字符串中的字符？

我正在编写一个简单的方法,将成绩作为用户的输入并计算成绩点平均值.这是我的代码:

public static double calculateGPA(){
   Scanner in = new Scanner(System.in);

   double totalGradePoints = 0; // total grade points
   int numClasses = 0; // total classes completed
   boolean doneInput = false; // returns true when use is done inputting grades

   System.out.println("Enter all your grades (A,B,C,D,F) and enter 'done' if you are done entering your grades.");  
   while (!doneInput) {     
      String grade = in.next();

      if (grade == "A") {
         totalGradePoints += 4;
         numClasses++;
      } else if (grade == "B") {
         totalGradePoints += 3; …