Question

这是我第一次尝试Java。该项目是一个计算器，它接受一个数字，一个运算符信号（+，-，*，/）和另一个数字以创建一个方程式并给出其最终值，然后询问用户是否要重新启动该程序以是否有其他方程式。我想知道我是否可以做些改进我的代码的事情。谢谢！

/*
Name: Felipe de Araujo
Project #: 1
*/

import java.util.Scanner; //Importing API.

public class Calculator {
public static void main(String[] args){
    int a = 1; //Creating variable for the first while loop.
    System.out.println("Welcome to the calculator!"); //Program introduction.

    while (a == 1){
        Scanner input = new Scanner(System.in); //Creating the input.

        double firstNumber, secondNumber, result; char operator; //Creating all variables.

        //Program asking for the first number.
        System.out.print("First Number: ");
        firstNumber = input.nextDouble();

        //Program asking for the operator
        System.out.print(firstNumber + " (+,-,*,/): ");
        operator = input.next(".").charAt(0);

        int repeat = 1; //Creating variable for the next while loop.

        //Evaluating the operator to determine if it is inside the criteria (+,-,*,/).
        if (operator == '+' || operator == '-' || operator == '*' || operator == '/'){
            System.out.print(firstNumber + " " + operator + " Second Number: "); //If the operator is inside the criteria than start
                                                                                 //asking for the second number.
        }
        else { //If the operator is not inside the criteria run the loop until the user type something that is.
            while (repeat == 1){
                System.out.print(operator + " not recognized, please select between (+,-,*,/): ");
                operator = input.next(".").charAt(0);
                if (operator == '+' || operator == '-' || operator == '*' || operator == '/') {
                    System.out.print(firstNumber + " " + operator + " Second Number: ");

                    repeat++;
                }
            }
        }

        secondNumber = input.nextDouble(); //Initialize the secondNumber variable to the number typed.

        //Equalling the variable result to the return given by the method calculatorMethod, with the variables given.
        result = calculatorMethod(firstNumber, secondNumber, operator);
        System.out.println(firstNumber + " " + operator + " " + secondNumber + " = " + result);//Printing the equation.
        System.out.println(" ");

        // Asking the user to continue the program for another operation.
        char out;//Creating the variable out.
        System.out.print("[y/Y] - continue | [n/N] or any other to end program: ");
        out = input.next(".").charAt(0);//Initializing the variable out to what was typed.

        //Verifying if the user wants to continue the program.
        if (out == 'y' || out == 'Y'){
            System.out.println(" ");
        }
        else {//If the users type anything besides y/Y the program will exit the main loop, ending the program.
            System.out.println("Bye!");
            a++;
        }
    }
}

//Declaring the calculatorMethod and all its behaviors.
private static double calculatorMethod(double a, double b, char c){

    if (c == '+'){
        return a + b;
    }
    else if (c == '-'){
        return  a - b;
    }
    else if (c == '*'){
        return a * b;
    }
    else {
        return a / b;
    }
}

}

Answer 1

您好，欢迎来到Java世界:)。一些提示：

尝试给变量明确名称。 'a'，'b'，'c'可能很难理解。
最常用的简短方法来提高代码的可读性。例如，您可以创建另一个方法，该方法返回以下对象：分隔符+两个数字，另一个返回结果。

您可以在 calculatorMethod 方法中使用 switch（变量）。例如：

switch (c) { // you have to change the name of all the variables 'c', 'a' and 'b'
    case '+':
        return a + b;
    case '-':
        return a - b;
    case '*':
        return a * b;
    default:
        return a / b;
}

}

您可以使用不同的运算符创建一个枚举或列表。
当检查输入运算符时，可以使用 while（）循环并删除 if ... else 循环。 while循环的条件可能是“当运算符不是正确的运算符时（因此，不包含在正确的运算符列表中），一次又一次地循环”。
扫描仪初始化扫描仪输入=新的Scanner（System.in）; 应该位于 while（）循环之外，因为您只需初始化一次扫描仪，在这种情况下，您需要初始化X次（X表示循环数）。

祝你好运:)

Java计算器（我的第一个项目需要帮助）

1 个答案: