May 30, 2021 Article blog
format:
for (initialization statement 1; J udgment Statement 2; S tep Statement 3)
Loop code 4
}
To execute the process:
First execute 1 initialization statement
Execute 2 judgment statements if the judgment results in true
Execute the 4-loop code
Execute a 3-step statement
Continue back to 2 4 3 2 4 3
If the result is false, it represents the end of the loop
note:
The initialization statement is executed only in the first loop and no longer after that
Code walkthrough:
public static void main(String[] args) {
/*
Judgment 0-10 qi
*/
// Even: The number that can be referred to by 2 is called an even number
// 0 is a special even number
for(int i=0;i<=10;i++){
if (i%2 == 0){
System.out.println (i + "is even");
}else {
System.out.println (i + "odd");
}
}
}
format:
Initialization statement 1;
while (judgment statement 2)
Loop code 3;
Step statement 4;
}
To execute the process:
1 Initialize the statement
2 Execute the judgment statement, execute the code in braces if it is true, and end the loop if it is false
3 Loop code
4 step statement
Loop through the 2 judgment statements again
Code walkthrough:
public static void main(String[] args) {
/*
Seeking 1-100 accumulation and
*/
int x = 1;
int sum = 0;
while (x<=100){
sum += x;
x++;
}
System.out.println ("1-100 is accumulated and:" + Sum);
}
format:
Initialization statement 1;
do{
Loop Statement 2;
Step Statement 3;
while (judgment statement 4);
To execute the process:
1 Initialize the statement
2 Loop statement
3 step statement
4 Judgment statement, if the result of the judgment is true to continue the loop, if the result of the judgment is false to end the loop
note:
The do-while loop is executed after execution, regardless of whether the condition is met or not
Code walkthrough:
public static void main(String[] args) {
/*
Output 1-10 and
*/
int a = 1;
int sum = 0;
do {
sum += a;
a++;
}while (a<=10);
System.out.println ("1-10 and:" + Sum);
}
All three cycle structures can achieve corresponding functions and choose a simpler form according to actual needs. Here's a summary of the usage scenario:
Code Walkthrough 1
public static void main(String[] args) {
/*
Cycle nested:
Outer cycle is performed once, the memory loop is executed
*/
/*
Circular from 0:0am - 23:59
*/
// Traverse the hour
for (int i=0; i<24; i++){
// Traverse minute
for (int j=0; j<60; j++){
System.out.println (i + "point" + J + "points");
}
}
public static void main(String[] args) {
for (int i = 1; i < 10; i++) {
System.out.println ("You are the" + i + "Bit Customer");
while (true) {
System.out.println ("Please select the item you want to purchase: 1. Fruit 2. Vegetables 3. Beverage 4. End purchase");
Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
if (a == 1) {
System.out.Println ("You buy fruit");
} else if (a == 2) {
System.out.Println ("You buy vegetables");
} else if (a == 3) {
System.out.println ("You purchased a drink");
} else if (a == 4) {
break;
} else {
System.out.println ("The instruction you entered");
}
}
}
}
1.while(true){...}
2.for(; ;){...}
Recommended lessons: Java micro-class, Java multithreaded explanation