Like any programming language, Java uses conditional statements and loop structures to determine the flow of control. This article will briefly explain conditions, loops and switches.
1. Block scope
Block (block) is a compound statement. It refers to several simple Java statements enclosed by a pair of curly brackets. Blocks determine the scope of variables.
For example:
1 public class Code { 2 static 3 { 4 System.out.println("1"); 5 } 6 { 7 System.out.println("2"); 8 } 9 public Code()10 {11 System.err.println("3");12 }13 public static void main(String[]args)14 {15 new Code();16 }17 }Note: Variables with the same name cannot be declared in two nested blocks.
2. Conditional statement
Format 1:
if(condition)
{
statement1
statement2
.....
}
For example:
1 if(youSales>=target)2 {3 performance="Satisfactory";4 bonus=1000;5 }Format 2 ：
if (condition) statement1 else statement2
For example:
1 if(youSales>=target） 2 ｛ 3 performance=“Satisfactory”； 4 bonus=100+10*（youSales-target“）； 5 ｝ 6 else 7 ｛ 8 performance=”Unstatisfactory“； 9 bonus=0；10 ｝
3. Loop
When the condition is true, the while loop executes.
Format 1:
while(condition)statemnet
For example:
1 while (balance
Format 2:
do statement while(condition);
1 do 2 { 3 balance+=payment; 4 double interest=balance*interestRate/100; 5 balance+=interest; 6 7 year++; 8 9 System.out.printf("After year %d,your balance is %,.2f%,year,balance");10 11 System.out.print("Ready to retire?(Y/N)");12 input=in.next();13 }14 while(input.equals("N"));15 16 }4. Determine the loop
The for loop statement is a general structure that supports iteration, using each A counter or similar variable updated after iterations to control the number of iterations.
The format is similar to the following:
for（int i=0; i System.out.println(i); 4 examples: 5. Multiple selection: switch statement The format is similar to the following: switch（choice） ｛ case 1： ..... break; case 2: ...... break; ...... //You can have a few more cases (end them with break) default: .... break; ｝ Note: case tag can be: * Type is char, byte, short or a constant expression of int. * Enum constants * Starting from Java SE 7, case labels can also be string literals. The above is the detailed content of Detailed introduction to using conditional statements and loop structures in Java. For more information, please follow other related articles on the PHP Chinese website! 1 public class ShuZu1 { 2 public static void main(String[]args){ 3 int [][] x={{1,2,2,2,2},{3,3,3,3,3},{4,5,-1,17,55}}; 4 int result=qiuHe(x); 5 System.out.println("和是"+result); 6 } 7 public static int qiuHe(int[][]x){ 8 int s=0; 9 for(int i=0;i 1 public class ShuZu2 { 2 public static void main(String[]args){ 3 int [][] x=new int[7][7]; 4 //生成随机数组，注意没有返回值，另外打印一行字 5 suiJi(x); 6 System.out.println("生成的数组是："); 7 8 //显示数组内容，注意没有返回值 9 showArray(x);10 11 //取值12 float result=getAvg(x);13 System.out.println("平均数是"+result);14 15 }16 static float getAvg(int [][] x){17 float s=0;18 for(int i=0;i 1 import java.util.Arrays; 2 public class SuZu3{ 3 public static void main(String[] args) { 4 int [] x={2,-1,7,777,6,764,85896,65554,0,874785,417825,74};
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