Control Statements In Java: A Detailed Guide (2021)

Introduction

A java program includes statements that are basically a  manual or a guide to explain how the procedure needs to happen in the program. These are alternatively called control statements in java. Such statements are introduced to provide a clear whole command and it may include different variables to execute them properly. When the user wants to multiply variables or add a sum of variables and print the result but he doesn’t want to keep writing the print command repeatedly, then in such cases he can use control statements in java.

Control statements in java  can be of three types :

• Declaration statements
• Expression statements
• Control flow statements

Control flow statements as the name suggests,  control the flow and execution of other statements in the program. Control flow statements define the sequence in which instructions are supposed to occur in the program. If the program wants to add any condition to the same, then is that possible? or if you want to repeatedly execute the same instruction? Certainly, that’s possible through the introduction of conditional control statements or iteration control statements.

These control statements in java can be further divided into three types :

1. Conditional control statements
2. Loop or Iteration control statements
3. Jump statements

1. Conditional control statements

These statements involve a condition and after evaluating the condition, the statements that fulfill that condition are chosen. Conditional control statements in java can be of the following types :

• If condition
• If else condition statement
• If-else-if condition statement

• If conditional control statements

These conditional statements in java involve installing an “If” condition and it’s used in a true or false form. In other words, it will always give two values, one value if the condition specified is true and another value if it’s false. True value will always be non zero and false value can be zero.

For example

if(X > 0) {print “welcome summer”;}

This means if the value of “X” is greater than zero then “welcome summer” will be printed.

• If else condition control statement

If else statements are basically a continuation of the “if” statements in java. This is introduced only when an “if” condition is introduced in the program. Then, if the value is true, the condition is executed in the “if” block and if the condition is false then the condition is executed in the “else” block. In both cases, after this step, the program is executed beyond the “if” block. The if-else expression is written like this :

If (condition)

{true block}

Else

{false block}

statements;

• If else if condition control statements

When there are multiple conditions involved then we use this kind of conditional control statements in java. In these statements, every statement is linked with else statements and then the end statement is an else statement.

2. Loop or Iteration control statements

A loop generally means creating a repetition structure. So a looping control statement involves inserting a condition wherein certain statements are run repeatedly until the condition or expression stated is satisfied. So if the condition specified does not get satisfied the code will keep on generating infinite loops. Looping statements in java are widely used when adding various sums of numbers or when you desire a consistent result of a certain process.

There are two main types of looping statements in java  :

• While loops

While loops are one of the simplest and popular forms of loops. They keep repeating the codes until the condition is met. For example, if we want to know how many times a number can be divided by 5 before it equals or less than 1, then we will create a while loop. If we already know the value of the number then no while loop condition is needed.

So in another word, the number has to be unknown while creating a while looping control statements in java.

• Do while loops

This kind of loop control system is executed usually when there are multiple calculations involved. Unlike the while loops, where until the condition is met the loop keeps repeating, here even if the condition is not met even then the loop body is executed once. So, in other words, we can say that in the “do while” loop, the loop is already executed, and then conditions are verified if met or not. That’s why it’s also called an exit-controlled loop.

3. Jump statements

Jump statements in java involve jumping from one statement to another to break or escape the execution of the code. These are introduced to interrupt any loop statements or switch statements. All of this is done unconditionally. Types of the jumping statements in java are  :

• Break statements

These are basically used to break the loop and are simply written as “break;” in the code. If this is used then the loop starts from the next statement.

• Continue statements

Unlike the break statement, this does not terminate the loop. Instead, it transfers the control to the beginning of the loop and the loop is repeated until the condition becomes false.

• Return statements

Return statements mean returning the value of the function to the caller of the function. It puts a stop to any further execution of a program. These jump statements are compulsory to use for all java methods.

CONCLUSION

After reading the above article you have a basic idea of the types of control statements in java. To conclude, we would just like to say that Control statements are the backbone of java programming and without them, java won’t be able to execute its functions smoothly and efficiently.

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