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

Let’s 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.