//trim()是用于删除前后多余的空格,composite.trim();以后为什么就剩hello等
What will be written to the standard output when the following program is run?public class Q03e4 {
public static void main(String args[]) {
String space = " ";
String composite = space + "hello" + space + space;
composite.concat("world");//composite变成 hello world
String trimmed = composite.trim();//????/
System.out.println(trimmed.length());
}
}
[Select One][1]5[2]6[3]7[4]12[5]13[Correct Choice]1
为什么是1呢,谢谢!
What will be written to the standard output when the following program is run?public class Q03e4 {
public static void main(String args[]) {
String space = " ";
String composite = space + "hello" + space + space;
composite.concat("world");//composite变成 hello world
String trimmed = composite.trim();//????/
System.out.println(trimmed.length());
}
}
[Select One][1]5[2]6[3]7[4]12[5]13[Correct Choice]1
为什么是1呢,谢谢!
String newString = composite.concat("world");
newString "hello world"
composite "hello"
composite.concat("world");//composite变成 hello world
//////////////////////////////////////////////////////返回一个对象是“hello world ”
但是composite自己没有变,仍然是:" hello "看一看API 写得很清楚//////////////////////
Concatenates the specified string to the end of this string.
If the length of the argument string is 0, then this String object is returned. Otherwise, a new String object is created, representing a character sequence that is the concatenation of the character sequence represented by this String object and the character sequence represented by the argument string.Examples: "cares".concat("s") returns "caress"
"to".concat("get").concat("her") returns "together"