Dart Programming - If Else Statement


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The else…if ladder is useful to test multiple conditions. Following is the syntax of the same.

if (boolean_expression1) { 
   //statements if the expression1 evaluates to true 
} 
else if (boolean_expression2) { 
   //statements if the expression2 evaluates to true 
} 
else { 
   //statements if both expression1 and expression2 result to false 
} 

When using if…else statements, there are a few points to keep in mind.

  • An if can have zero or one else's and it must come after any else…if's.

  • An if can have zero to many else…if's and they must come before the else.

  • Once an else…if succeeds, none of the remaining else…if's or else's will be tested.

Example - else…if ladder

The following program code checks whether a given value is positive, negative, or zero.

void main() { 
   var num = 2; 
   if(num > 0) { 
      print("${num} is positive"); 
   } 
   else if(num < 0) { 
      print("${num} is negative"); 
   } else { 
      print("${num} is neither positive nor negative"); 
   } 
}  

The following output is displayed on successful execution of the above code.

2 is positive
dart_programming_decision_making.htm
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