Question

大家好，我想知道你是否可以帮助我，你能不能告诉我这里我做错了什么，我想要做的是如果输入r则加1，如果输入L则输出减去1上层病例。但是这个位置不断回归原作。请帮助!!

    int position = 0;
    System.out.print("move: ");
    String car = Global.keyboard.nextLine();
    if (car == "r/")
        position =  + 1;
    if (car == "R")
        position = +1;
    if (car == "l")
        position =  -1;
    if (car == "L")
        position = -1;
        System.out.print(position);

Answer 1

使用：

int position = 0;
System.out.print("move: ");
String car = Global.keyboard.nextLine();
if (car.equals("r"))
    position += 1;
if (car.equals("R"))
    position += 1;
if (car.equals("l"))
    position -= 1;
if (car.equals("L"))
    position -= 1;
    System.out.print(position);

Answer 2

如果你想要1个衬垫，请使用：

position += car.equalsIgnoreCase("r") ? 1 : car.equalsIgnoreCase("l") ? -1 : 0;

Answer 3

使用以下其中一种风格：

position += 1
position -= 1

或

position = position + 1
position = position - 1

从值中添加或减去1。目前，您只需为其指定值+ / - 1。

Answer 4

用car.equals（“something”）替换每辆车==“某事”

像这样：

String car = Global.keyboard.nextLine();
if (car.equals("r"))
    position =  + 1;
if (car.equals("R"))
    position = +1;
if (car.equals("l"))
    position =  -1;
if (car.equals("L"))
    position = -1;
    System.out.print(position);

Answer 5

不要使用多个if s（应该是if - else语句，所以你不要在每种情况下都不要吝啬）和String s，请记住你可以{{ 1}} switch：

char

另外，请注意我更改了您的职位更新。要解决您当前的问题，int position = 0; //int dx = 1; For this case, the explanation is in a comment below. System.out.print("move: "); char car = Global.keyboard.nextChar(); switch(car) { case 'r': case 'R': position += 1; //Or position++ if you prefer, but I'd use this approach //just in case you want to do position += 5 in the future //or better yet, position += dx, being dx an int that //defines the range of a single movement. break; case 'l': case 'L': position -= 1; //Same as with right, but position -= dx; break; default: System.out.println("Please, use r - R for (R)ight or l - L for (L)eft"); break; } System.out.print(position);不应用于比较==，因为它会比较引用。请改用Strings。

需要帮助整理这个运动功能

5 个答案: