Dart Programming - Logical Operators

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Example

The following example shows how you can use Logical Operators in Dart −

 void main() { var a = 10; var b = 12; var res = (a<b)&&(b>10); print(res); } 

It will produce the following output −

 true 

Example

Lets take another example −

 void main() { var a = 10; var b = 12; var res = (a>b)||(b<10); print(res); var res1 =!(a==b); print(res1); } 

It will produce the following output −

 false true 

Short-circuit Operators (&& and ||)

The && and || operators are used to combine expressions. The && operator returns true only when both the conditions return true.

Let us consider the following expression −

 var a = 10 var result = (a<10 && a>5) 

In the above example, a<10 and a>5 are two expressions combined by an && operator. Here, the first expression returns false. However, the && operator requires both the expressions to return true. So, the operator skips the second expression.

The || operator returns true if one of the expressions returns true. For example −

 var a = 10 var result = ( a>5 || a<10) 

In the above snippet, two expressions a>5 and a<10 are combined by a || operator. Here, the first expression returns true. Since, the first expression returns true, the || operator skips the subsequent expression and returns true.

Due to this behavior of the && and || operator, they are called as short-circuit operators.