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Advanced Programming Techniques in D

Solution: Lets Play Cards

Explore how to define and use structs for card values and suits in D programming. Understand contract programming for error prevention and implement functions to build and shuffle a deck of cards, enhancing your struct and algorithm skills.

We'll cover the following...

Problem 1: Solution

D
struct Card {
    dchar suit;
    dchar value;
}
void main () {
}

Solution explanation

  • Lines 2 and 3:

Since we have to store the value and suit of the card, one of the simplest designs is to use two dchar members.

Problem 2: Solution

D
import std.stdio;
struct Card {
    dchar suit;
    dchar value;
    
    this(dchar s, dchar v) { // constructor
        suit = s;
        value = v;
    }
}
void printCard(Card card) {
    write(card.suit, card.value); 
}
void main() {
    auto card =  Card('♠','4');
    printCard(card);
}

Solution explanation

  • Line 14:

Our goal is to print the suit shape and value together, so we are using the write function here, which has two parameters: card.suit and card.value.

Problem 3: Solution

D
import std.stdio;
struct Card {
    dchar suit;
    dchar value;
}
void printCard(Card card) {
    write(card.suit, card.value); 
}
Card[] newDeck()
out (result) {
    assert(result.length == 52); 
} do {
    Card[] deck;
    deck ~= newSuit('♠'); 
    deck ~= newSuit('♡'); 
    deck ~= newSuit('♢'); 
    deck ~= newSuit('♣');
    return deck;
}
Card[] newSuit(dchar suit)
in {
    assert((suit == '♠') || 
           (suit == '♡') || 
           (suit == '♢') ||
           (suit == '♣'));
} out (result) {
    assert(result.length == 13); 
} do {
    Card[] suitCards;
    foreach (value; "234567890JQKA") {
        suitCards ~= Card(suit, value); 
    }
    return suitCards;
}
void main() {
    Card[] deck = newDeck();
    int count;
    foreach (card; deck) {
        printCard(card);
        write(' '); 
        count++;
        if(count%13 == 0)
        {
            writeln();
        }
    }
    writeln();
}

Solution explanation

  • Lines 17 - 20
...