With the continuous development of computer technology, programming languages are also emerging. Among them, Java, as a widely used programming language, is favored by programmers. This article will provide beginners with an ultra-detailed Java tutorial, including three examples, and explain and analyze them one by one, and finally give a question that synthesizes the knowledge points of the article and give the answer.
Java is an object-oriented programming language with characteristics of cross-platform and high security. First of all, we need to understand the basic syntax of Java, such as data types, operators, loop statements, and conditional statements. Below, we will demonstrate the basic grammar and application of Java with three examples.
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advantage
- Almost all Java libraries are supported.
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- Built-in debugger.
- Support trial operation.
shortcoming
- There is no automatic coding suggestion feature.
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The first example is a simple Hello World program that outputs the string "Hello World!". code show as below:
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello World!");
}
}The main components of this program are classes and methods. A class is the basic unit in Java, and all programs must contain a class. A method is a function in a class. In Java, all programs must contain a main() method, which is the entry point of the program. In the above code, we defined a class named HelloWorld, and defined a method named main() in it, which is used to output the string of "Hello World!".
The second example is a simple addition program that calculates the sum of two numbers and outputs the result. code show as below:
public class Add {
public static void main(String[] args) {
int a = 5;
int b = 10;
int c = a + b;
System.out.println("The sum of " + a + " and " + b + " is " + c);
}
}In this program, we define three variables a, b and c, which are used to store two numbers and their sum respectively. When outputting the result, we use the string connector "+" to connect the variable and the string together to form a complete string.
The third example is a simple loop program that outputs all integers from 1 to 10. code show as below:
public class Loop {
public static void main(String[] args) {
for (int i = 1; i <= 10; i++) {
System.out.println(i);
}
}
}In this program, we use the for loop statement to traverse all the integers from 1 to 10, and use the System.out.println() method to output each integer.
The above three examples have demonstrated the basic grammar and application of Java. Beginners can use these examples to deeply understand the characteristics and usage of Java. Finally, we give a question that synthesizes the knowledge points of the article, and give the answer.
Topic: Write a program that calculates the sum of all even numbers from 1 to 100 and outputs the result.
code show as below:
public class Sum {
public static void main(String[] args) {
int sum = 0;
for (int i = 1; i <= 100; i++) {
if (i % 2 == 0) {
sum += i;
}
}
System.out.println("The sum of all even numbers from 1 to 100 is " + sum);
}
}The above are the ultra-detailed tutorials and examples of Java. I hope that beginners can learn and master the basic syntax and applications of Java, so as to lay a solid foundation for future programming.