Java 用 printf 打印一个布尔值
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Print a boolean value with printf
提问by darbulix
I want to print a booleanvalue with the printf,but I do not know how. What I am looking for is something like this imaginary code
我想用 打印一个boolean值printf，但我不知道如何。我正在寻找的是类似这个虚构代码的东西
boolean car = true;
System.out.printf("%b",car);
The expected output should be:
预期的输出应该是：
true
How should I do it? Or are there any other ways to get that expected output?
我该怎么做？或者有没有其他方法可以获得预期的输出？
回答by sinister
The good thing is that it prints the value true, there is nothing wrong with your imaginary code. Alternatively you can also try
好消息是它打印了 value true，你想象中的代码没有任何问题。或者你也可以尝试
boolean car = true;
System.out.print(car);
System.out.printf("%b", car);
回答by Elliott Frisch
I assume you are running into a buffering issue, such that your program exits before your buffer flushes. When you use printf()or print()it doesn't necessarily flush without a newline. You can use an explicit flush()
我假设您遇到了缓冲问题，以至于您的程序在缓冲区刷新之前退出。当您使用printf()orprint()它不一定在没有换行符的情况下刷新。您可以使用显式flush()
boolean car = true;
System.out.printf("%b",car);
System.out.flush();
or add a new-line (which will also cause a flush())
或添加一个新行（这也会导致flush()）
boolean car = true;
System.out.printf("%b%n",car);
See also Buffered Streams - The Java Tutorials, Flushing Buffered Streamswhich says in part
另请参阅Buffered Streams - The Java Tutorials, Flushing Buffered Streams部分说明
Some buffered output classes support autoflush, specified by an optional constructor argument. When autoflush is enabled, certain key events cause the buffer to be flushed. For example, an autoflush
PrintWriterobject flushes the buffer on every invocation ofprintlnorformat.
一些缓冲输出类支持autoflush，由可选的构造函数参数指定。启用自动刷新后，某些关键事件会导致缓冲区被刷新。例如，自动刷新
PrintWriter对象在每次调用printlnor 时刷新缓冲区format。
回答by Vlad
boolean car =true;
System.out.println(""+car);
