Hello, and welcome to the world of Java programming! In this article, we'll discuss the basics of Java's control structures, specifically if/else statements, switch statements, and loops.
Control Structures: If/Else Statements
If/else statements are conditional statements that allow us to make decisions based on a given condition. In Java, the syntax for an if/else statement is as follows:
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if (condition) {
// code to execute if the condition is true
} else {
// code to execute if the condition is false
}
For example, suppose we want to write a program that determines whether a given number is even or odd. We can use an if/else statement to accomplish this task, like so:
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int number = 5;
if (number % 2 == 0) {
System.out.println("The number is even.");
} else {
System.out.println("The number is odd.");
}
In this example, the condition is number % 2 == 0, which checks whether the remainder of the number divided by 2 is equal to 0. If the condition is true, we print "The number is even." If the condition is false, we print "The number is odd."
Control Structures: Switch Statements
Switch statements are conditional statement that allows us to choose between different cases based on a given condition. In Java, the syntax for a switch statement is as follows:
java
switch (variable) {
case value1:
// code to execute if variable equals value1
break;
case value2:
// code to execute if variable equals value2
break;
...
default:
// code to execute if none of the cases match
break;
}
For example, suppose we want to write a program that takes a grade (A, B, C, D, or F) and prints a message based on the grade. We can use a switch statement to accomplish this task, like so:
csharp
char grade = 'B';
switch (grade) {
case 'A':
System.out.println("Excellent!");
break;
case 'B':
System.out.println("Good job!");
break;
case 'C':
System.out.println("OK.");
break;
case 'D':
System.out.println("You can do better.");
break;
case 'F':
System.out.println("Try again.");
break;
default:
System.out.println("Invalid grade.");
break;
}
In this example, we use a switch statement to check the value of the grade variable and print a message based on the value. If the grade is 'B,' we print "Good job!".
Control Structures: Loops
Loops are structures that allow us to repeat a block of code multiple times. In Java, there are three loops: for loops, while loops, and do-while loops.
Loops are used when we know the number of times we want to repeat a block of code. The syntax for a for loop is as follows:
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for (initialization; condition; update) {
// code to execute in the loop
}
For example, suppose we want to write a program that prints the numbers 1 to 10. We can use a for loop to accomplish this task, like so:
css
for (int i = 1; i <= 10; i++) {
System.out.println(i);
}
In this example, the loop starts with i = 1 and repeats as long as i <= 10. Each time the loop repeats, we print the value of.`
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