Question

当我使用problem1对象调用方法“getUnknownsAccel”时，由于某种原因，方法中的'if'语句不会被执行以检索变量的值：

PhysicsProblem problem1 = new PhysicsProblem(accel, vI, vF, t, deltaX);

    System.out.println("Which variable are you solving for? ");
    String solveFor = scan.next();


    // after receiving solveFor input, assesses data accordingly

    if (solveFor.equalsIgnoreCase("acceleration"))
    {
        System.out.println("Solving for Acceleration!");
        System.out.println("Are there any other unknowns? (enter 'none' or the name " +
                "of the variable)");
        missingVar = scan.next();
        problem1.setMissingVar(missingVar);
        do
        {
            problem1.getUnknownsAccel();
            System.out.println("Are there any other unknowns? (enter 'none' or the name " +
                    "of the variable)");
            missingVar = scan.next();               //// change all these in the program to scan.next, not scan.nextLine
        }
        while (!missingVar.equalsIgnoreCase("none") || !missingVar.equalsIgnoreCase("acceleration"));

        if (missingVar.equals("none"))
        {
            // Write code for finding solutions
            System.out.println("Assuming you have given correct values, the solution is: ");
        }
    }

在用于检索未知其他变量名称的do / while循环之后，我从此类文件中调用getUnknownsAccel方法：

public void getUnknownsAccel()
{
    //-----------
    // checks for another unknown value that is not accel
    //-----------
    if (missingVar.equalsIgnoreCase("time"))
    {
        System.out.println("Please enter the value for time: ");
        t = scan.nextDouble();
        while (t <= 0 || !scan.hasNextDouble())
        {
            System.out.println("That is not an acceptable value!");
            t = scan.nextDouble();
        }
    }       

}

让我们假设为了这个问题，用户将在提示时输入“时间”作为未知。知道为什么我的代码没有执行扫描功能来检索时间变量值吗？相反，程序只是重复system.out函数“还有其他任何未知数......”

Answer 1

扫描完成后，将missingVar设置为scan.next（），但不执行任何操作。循环继续。

之后

missingVar = scan.next();

添加行

getUnknownsAccel();

注意，另一个问题是你需要稍后处理的是missingVar是本地的 - 要在getUnknownsAccel（）中访问它，你应该将声明更改为

public void getUnknownsAccel(String missingVar){
}

而是使用 getUnknownsAccel（missingVar）;

我需要弄清楚我的代码中的逻辑错误

1 个答案: