Decision Making in Java (if, if-else, switch, break, continue, jump)
Categories: Java 8(JDK1.8)
Decision Making in programming is similar to decision-making in real life. In programming also face some situations where we want a certain block of code to be executed when some condition is fulfilled.
A programming language uses control statements to control the flow of execution of a program based on certain conditions. These are used to cause the flow of execution to advance and branch based on changes to the state of a program.
Java’s Selection statements:
1. if
2. if-else
3. nested-if
4. if-else-if
5. switch-case
6. jump – break, continue, return
1. if: if statement is the most simple decision-making statement. It is used to decide whether a certain statement or block of statements will be executed or not i.e if a certain condition is true then a block of statement is executed otherwise not.
Syntax:
if(condition)
{
// Statements to execute if
// condition is true
}
Here, the condition after evaluation will be either true or false. if statement accepts boolean values – if the value is true then it will execute the block of statements under it.
2. if-else: The if statement alone tells us that if a condition is true it will execute a block of statements and if the condition is false it won’t. But what if we want to do something else if the condition is false. Here comes the else statement. We can use the else statement with if statement to execute a block of code when the condition is false.
Syntax:
if (condition)
{
// Executes this block if
// condition is true
}
else
{
// Executes this block if
// condition is false
}
3. nested-if: A nested if is an if statement that is the target of another if or else. Nested if statements mean an if statement inside an if statement. Yes, java allows us to nest if statements within if statements. i.e, we can place an if statement inside another if statement.
Syntax:
if (condition1)
{
// Executes when condition1 is true
if (condition2)
{
// Executes when condition2 is true
}
}
5. switch-case: The switch statement is a multiway branch statement. It provides an easy way to dispatch execution to different parts of code based on the value of the expression.
Syntax:
switch (expression)
{
case value1:
statement1;
break;
case value2:
statement2;
break;
.
.
case valueN:
statementN;
break;
default:
statementDefault;
}
4. if-else-if ladder: Here, a user can decide among multiple options.The if statements are executed from the top down. As soon as one of the conditions controlling the if is true, the statement associated with that if is executed, and the rest of the ladder is bypassed. If none of the conditions is true, then the final else statement will be executed.
if (condition)
statement;
else if (condition)
statement;
.
.
else
statement;