When you think about it, there\u2019s a lot of \u201cifs\u201d in our lives. If the grocery store is open, we can go in and buy groceries; otherwise, we cannot. If it\u2019s 12 noon, then it is time to take a lunch break.
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Programs rely just as much on \u201cifs\u201d as we do. In programming, \u201cifs\u201d are called conditional statements. These statements allow you to run or not run a block of code depending on whether a particular condition is met.
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In this guide, we\u2019re going to discuss how if statements work in Java and why they are useful. We\u2019ll walk through an example to demonstrate how they work.<\/p>\n\n\n\n
Sometimes, you don\u2019t want a specific line of code to run in your program. That\u2019s where conditional logic comes in. By using an The Open up a new Java file and paste in the following code: In this code, we have defined a variable called order which holds the string value \u201cHam Sandwich\u201d. We then use an if statement to check whether or order is equal to the term \u201cHam Sandwich\u201d. If it is, the price of a ham sandwich is printed. Run this Java program in your programming environment. You\u2019ll see the following response:<\/p>\n\n\n\n The order we have specified is \u201cHam Sandwich\u201d, so that line of code is run. Let\u2019s change our order to a chicken sandwich: Our code returns: Done. The contents of our if statement are not executed because our condition \u2013\u2260 order being equal to \u201cHam Sandwich\u201d \u2013 was not met.<\/p>\n\n\n\n The Let\u2019s say that we want our program to print: If our expression evaluates to false, the contents of our When we change our order back to \u201c Ham Sandwich\u201d, the output we received in the last example will be returned.<\/p>\n\n\n\n Say that we want to check for three different sandwiches in our program. Their prices are: To make our program work, we’re going to add in a few Our program can now return four possible outputs. If we run our above program, we\u2019ll receive the following response:<\/p>\n\n\n\n Let\u2019s change the value of our order variable to \u201cSmoked Salmon Sandwich\u201d and run our program again:<\/p>\n\n\n\n You can see that our program is now capable of evaluating multiple different conditions. We could add in as many as we wanted. If we were operating a cafe, we may want to evaluate against ten different conditions, one for each sandwich we sell.<\/p>\n\n\n\nif<\/code> statement, you can evaluate an expression, and depending on the outcome of that expression, run a block of code.
<\/p>\n\n\n\nif<\/code> statement evaluates whether a Boolean expression is false or true. If that expression is true, the code will be executed; if the expression is false, nothing will happen. Sometimes, if<\/code> statements are called control flow statements.
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<\/p>\n\n\n\nclass MenuPrices {\n\tpublic static void main(String[] args) {\n\t\tString order = \"Ham Sandwich\";\n\t\tif (order.equals(\"Ham Sandwich\")) {\n\t\t\tSystem.out.println(\"The price of a \" + order + \" is $1.95.\");\n\t\t}\n\t\tSystem.out.println(\"Done\");\n\t}\n}<\/pre><\/div>\n\n\n\n
<\/p>\n\n\n\nThe price of a Ham Sandwich is $1.95.\nDone<\/pre><\/div>\n\n\n\n
<\/p>\n\n\n\nString order = \"Chicken Mayo Sandwich\";\nif (order.equals(\"Ham Sandwich\")) {\n\tSystem.out.println(\"The price of a \" + order + \" is $1.95. \");\n}\nSystem.out.println(\"Done\");<\/pre><\/div>\n\n\n\nIf Else Statements<\/h2>\n\n\n\n
if<\/code> statement is useful, but what if you want to do something else if your condition doesn\u2019t evaluate to true? That\u2019s where the aptly-named Java if else statement comes in.
<\/p>\n\n\n\nThis item is not on the menu.<\/code> If it cannot find the order we\u2019ve entered. We could do so by adding an else block to our code:
<\/p>\n\n\n\nString order = \"Chicken Mayo Sandwich\";\nif (order.equals(\"Ham Sandwich\")) {\n\tSystem.out.println(\"The price of a \" + order + \" is $1.95. \");\n}\nSystem.out.println(\"Done\");<\/pre><\/div>\n\n\n\nelse<\/code> statement will execute. When you save and run the program, you’ll see the following:<\/p>\n\n\n\nThis item is not on the menu.\nDone<\/pre><\/div>\n\n\n\n
Else if Statement<\/h2>\n\n\n\n
if..else<\/code> statements can handle two potential outcomes: whether a condition is met, or whether a condition is not met. We can use a statement called else if<\/code> to evaluate more conditions.
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else if<\/code> statements:<\/p>\n\n\n\nString order = \"Chicken Mayo Sandwich\";\nif (order.equals(\"Ham Sandwich\")) {\n\tSystem.out.println(\"The price of a \" + order + \" is $1.95. \");\n} else {\n\tSystem.out.println(\"This item is not on the menu.\");\n}\nSystem.out.println(\"Done\");<\/pre><\/div>\n\n\n\nThe price of a Chicken Mayo Sandwich is $2.20.\nDone<\/pre><\/div>\n\n\n\n
The price of a Smoked Salmon Sandwich is $3.00.\nDone<\/pre><\/div>\n\n\n\n