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What is an auto function in D programming?

Chinweuba Elijah Azubuike

What is a function?

Functions are code blocks that carry out specific executions in an application. This code block can be called more than once during the application’s runtime.

What is the Auto function?

Auto functions are functions without restrictions to their return value type. Let’s see an example.


import std.stdio;
auto multiply(int val1, double val2) { 
   double output = val1 * val2; 
   return output; 

void main() { 
   int x = 1; 
   double y = 2.5; 
   writeln("multiply(x,y) = ", multiply(x, y)); 
Example of Auto function

Code explanation

In the code example above we are performing a simple multiplication operation to demonstrate the auto function.

  • Line 2: We define our multiply function, notice the auto keyword used while declaring the function. We also passed in parameters that we use in the function.

  • Line 3: We define our variable output as a data type of double.

  • Line 4: We return the created variable even though it is a double data type.

  • Lines 8–9: We define and assign values to our variables x and y.

  • Line 11: We print out the result by calling the multiply function inside of the writeln() method.


d programming


Chinweuba Elijah Azubuike

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