小编ncw*_*ncw的帖子

从文章跳到文章,我随处都可以看到"批量加载"的表达方式.

它真正(技术上)意味着什么？

这意味着什么？

基于用例的解释是受欢迎的.

如何以矩阵框格式打印出一个简单的int [] [],就像我们手写矩阵的格式一样.简单的循环运行显然不起作用.如果它有助于我尝试在linux ssh终端中编译此代码.

for (int i = 0; i < rows; i++) {
    for (int j = 0; j < cols; j++) {
        System.out.println(matrix[i][j] + " ");
    }
    System.out.println();
}

我在OS X El Capitan上安装了Homebrew.在安装的最后几步中我应该安装git

brew install git

这很好.现在,如果我运行'brew doctor',就会发生这种情况:

$ brew doctor
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry and just ignore them. Thanks!

Warning: Git could not be found in your PATH.
Homebrew uses Git for several internal functions, and some formulae use Git
checkouts instead of stable tarballs. You may want to install …

这更像是理解Java对算术运算的评估的理论问题.由于+并-具有相同的优先级,我不太明白Java如何评估以下表达式(两个操作数之间有多个+和-运算符).

public static void main(String[] args) {
    int a = 1;
    int b = 2;
    System.out.println(a+-b);    // results in -1
    System.out.println(a-+b);    // results in -1
    System.out.println(a+-+b);   // results in -1
    System.out.println(a-+-b);   // results in  3
    System.out.println(a-+-+b);  // results in  3
    System.out.println(a+-+-b);  // results in  3
    System.out.println(a-+-+-b); // results in -1
    System.out.println(a+-+-+b); // results in  3
}

从Java 8语言规范(第15.8.2节):

当应用于两个数值类型的操作数时,binary +运算符执行加法,产生操作数的总和.
二元 - 运算符执行减法,产生两个数字操作数的差异.
[...]
如果操作数表达式没有副作用,则Addition是一个可交换操作.
当操作数都是相同类型时,整数加法是关联的.

我还注意到,每次#operators都是偶数时,结果是相同的,顺序无关紧要.但是当#operators是奇数时,这并不一定会影响结果.例如,在以下两个表达式有一个更-比+ …

每次输入String或Char时,我的read()方法都会崩溃.我怎么能让它只接受整数值.当我输入一个int,它工作正常,但当我输入一个字符串或字符串时,我得到一个重复的"输入帐户打开的那天:null"错误.我必须终止程序才能阻止它.

private void readDay(Scanner keyboardIn) {
    boolean success = false;
    while (!success) {
        try {
            System.out.print("Enter the day the account opened: ");
            int d = keyboardIn.nextInt();
            dateOpened.setDay(d);
            success = true;
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }
}

// Enter the month, checking for error
private void readMonth(Scanner keyboardIn) {
    boolean success = false;
    while (!success) {
        {
            try {
                System.out.print("Enter the month the account opened: ");
                int m = keyboardIn.nextInt();
                dateOpened.setMonth(m);
                success = true;
            } catch (Exception e) …