real simple delegate question.

WhatMeForget via Digitalmars-d-learn digitalmars-d-learn at puremagic.com
Thu Aug 17 19:38:15 PDT 2017


Can someone explain what is the difference between the two? 
Thanks.

module gates;
import std.stdio;
import std.random;

alias Calculator = int delegate(int);

Calculator makeCalculator()
{
     static int context = 0;
     int randy = uniform(1, 7);
     context++;
     writeln("context = ", context);
     writeln("randy = ", randy);
     return value => context + randy + value;
}

void main()
{
     for (int i = 0; i < 3; i++)
     {
         auto calculator = makeCalculator();
         writeln("The result of the calculation: ", calculator(0));
     }
}
returns:
context = 1
randy = 5
The result of the calculation: 6
context = 2
randy = 2
The result of the calculation: 4
context = 3
randy = 6
The result of the calculation: 9

while the following

void main()
{
     auto calculator = makeCalculator();  // thought just one 
would work
     for (int i = 0; i < 3; i++)
     {
         writeln("The result of the calculation: ", calculator(0));
     }
}
returns:
The result of the calculation: 3
The result of the calculation: 3
The result of the calculation: 3




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