Dart TypeDef

Examples of Typedef

Below given is a Dart program to demonstrate typedef usage: 

Let's start by defining a typedef. We're defining a function signature right now. The function will accept two integer-type input parameters(int a, int b), and the function signature does not include the return type.

Code:

typedef codeStudio(int a, int b); // Defining alias name
 
//  m1 function
m1(int a, int b) {
  print("You entered block m1");
  print("Adding $a + $b will be equal to ${a + b}.");
  print("");
}
 
// m2 function
m2(int a, int b) {
  print("You entered block m2");
  print("Multiplying $a * $b will be equal to ${a * b}.");
}
 
void main()   // Main method
{
  // Using alias name to define num
  codeStudio num= m1;    // num with m1 function

  num(10,100);    // Calling num
   
  // Redefining num
  num= m2;     // with m2 function

  num(2,3);    // Calling num
}

Output:

You entered block m1
Adding 10 + 100 will be equal to 110.

You entered block m2
Multiplying 2 * 3 will be equal to 6.

Apart from that, Typedef can also be used as function parameters.

So now, let's have a look at one more example of using Typedef as a function parameter.

Code:

typedef codeStudio(int x , int y);   //function signature
Adding(int x,int y){     // m1
   print("sum is ${x+y}");
}  
Subtracting(int x,int y){    //m2
   print("resultant is ${x-y}");
}  
Dividing(int x,int y){    //m3
   print("quotient is ${x/y}");
}  
Counter(int a,int b ,codeStudio operation){   // calling out operations
   print("Entering calci mode: ");
   operation(a,b);
}  
main(){ // main method
   Counter(10,20,Adding);
   Counter(30,40,Subtracting);
   Counter(50,60,Dividing);
}

Output:

Entering calci mode:
sum is 30
Entering calci mode:
resultant is -10
Entering calci mode:
quotient is 0.8333333333333334

Frequently Asked Questions

Is it possible to Typedef a typedef?

Except for type-specifiers, the typedef specifier cannot be coupled with any other specifier. The typedef-names are not declarations of new types but rather aliases for existing types. So, Typedef cannot be used to change the meaning of a type name that already exists (including a typedef-name).

Is it possible to Typedef a function in C?

The typedef keyword is used in the C programming to give out meaningful names to the variables that already exist in the program. It also works similarly to how we construct aliases for commands.

Can we make a typedef extern?

Every declarator in a declaration that uses Typedef as a storage-class specifier defines an identifier as an alias to the type provided. A typedef declaration cannot be static or extern because only one storage-class specifier is allowed in a declaration.

Conclusion

In this article, we learned about Dart TypeDef and from its declaration to usage with the implementation of examples.
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