java - toBinaryString 的前导为 1

Question

我在一个简单的计算器中使用 toBinaryString 将整数转换为其二进制等价物，每当进行除加法之外的任何数学运算时，我都会得到前导 1 和不应该出现的 0。

例如，我从 10 中减去 5，这应该得到二进制的 5 或 101，但我得到的是

Output: 11111111111111111111111111110001

这是我不知道的 toBinaryString 问题，还是我做错了什么？

主要代码:

    if (input == 1)
    {
        System.out.println("- ADDITION -");
        toDo = operator.getInputs(input); // Gets how many values to input.
        ArrayList<Integer> list = new ArrayList<>(toDo);
        operator.addToList(list, toDo); // Adds values input to list.
        operator.addBinary(list); // Add values in 'list' together.
    }

    if (input == 2)
    {
        System.out.println("- Subtraction -");
        toDo = operator.getInputs(input); // Gets how many values to input.
        ArrayList<Integer> list = new ArrayList<>(toDo);
        operator.addToList(list, toDo); // Adds values input to list.
        operator.subBinary(list); // Subtract values in 'list' for eachother.
    }

    if (input == 3)
    {
        System.out.println("- Multiplication -");
        toDo = operator.getInputs(input); // Gets how many values to input.
        ArrayList<Integer> list = new ArrayList<>(toDo);
        operator.addToList(list, toDo); // Adds values input to list.
        operator.multBinary(list); // Multiplies values in 'list' together.
    }

方法:

class binaryOperations
{
private Scanner scan = new Scanner(System.in);

int getInputs(int b)
{
    int input;
    System.out.println("How many integers do you wish to input: ");
    return input = scan.nextInt();
}

int printBinary(int b) // Number to convert
{
    String foo = Integer.toBinaryString(b); // Convert input to binary
    return (Integer.parseInt(foo));
}

ArrayList<Integer> addToList(ArrayList<Integer> list, int toDo)
{
    for (int i = 0; i < toDo; i++)
    {
        if (i == 0)
            System.out.println("Please enter the first integer:");
        else
            System.out.println("Please enter the next integer: ");

        int input = scan.nextInt();
        list.add(input);
    }
    return list;
}


// Addition //
void addBinary(ArrayList<Integer> list)
{
    int temp = 0, sum = 0;
    for (int i = 0; i <= list.size() - 1; i++)
    {
        temp = list.get(i);
        sum += temp;
    }

    String foo = Integer.toBinaryString(sum); // convert the sum to a string

    System.out.println("The sum of the numbers in binary is " + foo);
}

// Subtraction //
void subBinary(ArrayList<Integer> list)
{
    int temp = 0, difference = 0;
    for (int i = 0; i <= list.size() - 1; i++)
    {
        temp = list.get(i);
        difference -= temp;
    }

    String foo = Integer.toBinaryString(difference); // convert the difference to a string

    System.out.println("The difference of the numbers in binary is " + foo);
}

// Multiplication //
void multBinary(ArrayList<Integer> list)
{
    int temp = 0, products = 0;
    for (int i = 0; i <= list.size() - 1; i++)
    {
        temp = list.get(i);
        products *= temp;
    }

    String foo = Integer.toBinaryString(products);

    System.out.println("The products of the numbers in binary is " + foo);
}
}

Answer 1

您的 subBinary 无法正常工作。它的作用是:

0 - firstElementofList - secondElementofList ...

因此，在您的情况下，如果您的列表包含 {10,5}，您将得到 -15，它由以下二进制值精确表示:

11111111 11111111 11111111 11110001

您需要做的就是更改它，可能会从第一个中减去其余部分:

void subBinary(ArrayList<Integer> list)
{
    int temp = 0, difference = list.get(0);
    for (int i = 1; i <= list.size() - 1; i++)
    {
       temp = list.get(i);
       difference -= temp;
    }

    String foo = Integer.toBinaryString(difference); // convert the difference to a string

    System.out.println("The difference of the numbers in binary is " + foo);
}

现在，如果您提供 {5,10}，您将得到 -5