Possible Duplicate:
varargs and the '…' argument
Java, 3 dots in parameters
I saw this definition in my android java file. It looks just like String[]. Are they different? Thank you.
The duplicate characters in a string are those that occur more than once. These characters can be found using a nested for loop. An example of this is given as follows − String = Apple. In the above string, p is a duplicate character as it occurs more than once.
To find the duplicate character from the string, we count the occurrence of each character in the string. If count is greater than 1, it implies that a character has a duplicate entry in the string. In above example, the characters highlighted in green are duplicate characters.
The C library function to copy a string is strcpy(), which (I'm guessing) stands for string copy. Here's the format: char * strcpy(char * dst, const char * src);
To find the duplicate character from the string, we count the occurrence of each character in the string. If count is greater than 1, it implies that a character has a duplicate entry in the string. In above example, the characters highlighted in green are duplicate characters.
varags
. If a method signature is method(Param param, String... x)
it will take one Param
type of object and any number of String objects.
There are couple if cool things about it:
It's nothing special. It's just sugared array. So, method(MyObject... o)
is same as method(MyObject[] o)
.
Vararg has to be the last parameter in argument list.
There is this funny thing that bit me once. method(MyObject... o)
can be called as method()
without any compilation error. Java will internally convert the no-arg call to method(new MyObject[0])
. So, be aware of this.
It's syntax for writing the items of the array as a parameter
for instance:
public String first (String... values) {
return values[0];
}
Then you can call this method with first("4","2","5","67")
The javacompiler will create an array of the parameters on its own.
It's a vararg, variable number of arguments. In the method body you treat it as a String[], but when you call the method you can either chose to supply a String[] or simply enumerate your values.
void foo(String... blah) { }
void bar() {
String[] a = { "hello", "world" };
foo(a); // call with String[]
foo("hello", "world"); // or simply enumerate items
}
Was introduced with Java 5.
It's for defining a method with a variable number of arguments.
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