Introduction to Programming

if...else 

The if...else construct allows executing a certain statement or block if the expression evaluates to true; otherwise, another statement or block is executed:

if(Boolean expression){  //do something} else {  //do something else}

Here are two examples:

int x = 1, y = 1; if(x == y){                          System.out.println("x == y");  //prints: x == y  x = y - 1;} else {  System.out.println("x != y");  }if(x == y){                          System.out.println("x == y");} else {  System.out.println("x != y");  //prints: x != y}

You can see how easy it is to read this code when the braces {} are used consistently. And, as in the previous case of a simple if statement, each block can have another nested block with another if statement, and so on – as many blocks and as deeply nested as ...