JAVA learning lesson 3 (functions and their overloading)

JAVA learning lesson 3 (functions and their overloading)
Switch () applies to byte, short, int, char

If break is not added in case, it will be executed all the time, know}, or break.

For example:

public class Main {public static void main(String[] args){//int x = 5, y = 4,xx = 6;char a = 'f';switch(a){default :System.out.println("d");case 'a':System.out.println("a");case 'b':System.out.println("b");break;case 'c':System.out.println("c");break;}//System.out.println("56");}}

The execution result is d, a, and c.


Difference between if and switch
If:
1. determine the specific value
2. Determine the interval
3. Determine if the operation result is a boolean expression.


Switch:
1. determine the specific value
2. The number of values is fixed.
PS: For a few fixed values, it is best to use the switch, because the switch will load the specific answer into the memory at a time, the efficiency is relatively high
Switch is not commonly used, has poor functionality, and is difficult to write


In windows, the carriage return is \ r \ n;
Linux system is \ n


Function:

Function Definition:


Modifier (public can be added or not added to play the role of a permission) function type function name (parameter type parameter name, parameter type parameter name)
{
Execute the statement;
Return value;
}

Import java. util. extends; public class Main {public static void main (String [] args) {using cin = new using (System. in); int n = cin. nextInt (); int a = cin. nextInt (); int ans = sum (n, a); System. out. println ("ans =" + ans); int ans1 = sub (a, n); System. out. println ("ans1 =" + ans1); cin. close ();} static int sum (int a, int B) // do not add public {return a + B;} public static int sub (int a, int B) // Add public {return a-B ;}}

Function overloading:

Different from the function name and parameter types, the function features the same as that of the execution. For example, if all values are added, all values are subtracted and the maximum value is found.

Relatively simple and the features of C ++ are basically the same

Example code:

Import org. omg. cosNaming. namingContextExtPackage. addressHelper; public class Main {public static void main (String [] args) {int ans = add (4, 5); int sum = add (5, 6, 7); System. out. println (ans); System. out. println (sum);} static int add (int x, int y) {return x + y;} static int add (int x, int y, int z) {// return x + y + z; return add (x, y) + z;/* The defined amount function can be called. Therefore, the function is overloaded, there are some repeated functions that can be called to each other */}}