case study: focus on structures math 130 lecture 21 b smith: 10/04: required 35 minutes to complete....
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Case Study:Focus on Structures
Math 130
Lecture 21
B Smith:
10/04: Required 35 minutes to complete. 15 minutes was spent returning test 2 and completing the surveys. Good examples here
B Smith:
10/04: Required 35 minutes to complete. 15 minutes was spent returning test 2 and completing the surveys. Good examples here
B Smith:
Conisder skipping? No. There are good examples of use of structures, modulus, arrays of structures, pointers to struct.
B Smith:
Conisder skipping? No. There are good examples of use of structures, modulus, arrays of structures, pointers to struct.
B Smith:
Alex came in and discussed Mindstorms for 10 minutes, lecture took 40 to 45 min
B Smith:
Alex came in and discussed Mindstorms for 10 minutes, lecture took 40 to 45 min
B Smith:
10/31/05: time 45 minutes. Students were quite interested and challenged. Good “thinking” exercise. Rate: 3
B Smith:
10/31/05: time 45 minutes. Students were quite interested and challenged. Good “thinking” exercise. Rate: 3
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Overview
• Case Study deck of cards implementation shuffling simulation dealing
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Struct Case Study• card is the structure name and is used to declare variables of the
structure type• card contains two members of type char *
Namely, the members are face and suit.
struct card { char *face;//rank char *suit;//4suits};
struct card{char *face; char *suit;};
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typedef• Used to create shorter type names
• Allows for an alias or a pseudonym to be used as shorthand notation for previously defined names
• An example would be
typedef struct card Card;
• So have we created a new data type? No, only an alias, a synonym
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Initialization, Assignment
• Can be initialized using the following methods:
Card oneCard = {“Seven”, “Diamonds”};
or:
Card sevenDiamonds = oneCard;
or member by member:
Card sevenDiamonds;
sevenDiamonds.face = “Seven”;
sevenDiamonds.suit = “Diamonds”;
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Structure Member Access
• Accessing the structure’s members Dot operator ( . )
Arrow operator ( -> ) is used with pointers to structure variables
cardPtr->suit is equivalent to (*cardptr).suit
Card myCard;printf(“%s”, myCard.suit);
Card *cardPtr=&myCard;printf(“%s”, cardPtr->suit);
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Conditional Expressions
• The operator ?: provides another way of implementing an if-else condition
• The format is:
expression1 ? expression2 : expression3
expression1 is evaluated: • if it is non-zero, the result is the value of expression2, • otherwise the result is derived from expression3
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Conditional Expression Example
if (hours > 40) rate = payRate*1.5;else rate = payRate;
rate = (hours > 40) ? payRate*1.5 : payRate
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Example• Card Shuffling and Dealing Program Using Structures
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main()
#include <stdio.h>#include <stdlib.h>#include <time.h>
struct card { char *face; char *suit; }; typedef struct card Card; /* new type name for struct card */
void fillDeck( Card * wDeck, char * wFace[], char * wSuit[] );void shuffle( Card * wDeck );void deal(Card * wDeck );
int main()
{ ...
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main()
int main(){ Card deck[ 52 ]; char *face[] = { "Ace", "Deuce", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Jack", "Queen", "King"};
/* initialize array of pointers */ char *suit[] = { "Hearts", "Diamonds", "Clubs", "Spades"};
srand( time( NULL ) ); /* randomize */
fillDeck( deck, face, suit ); /* load the deck with Cards */ shuffle( deck ); /* put Cards in random order */ deal( deck ); /* deal all 52 Cards */
return 0; /* indicates successful termination */
}
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fillDeck()
/* place strings into Card structures */void fillDeck( Card * wDeck, char * wFace[], char * wSuit[] ){ int i;
for ( i = 0; i <= 51; i++ ) { wDeck[ i ].face = wFace[ i % 13 ]; wDeck[ i ].suit = wSuit[ i / 13 ]; }
}
char *face[] = { "Ace", "Deuce", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Jack", "Queen", "King"};
/* initialize array of pointers */ char *suit[] = { "Hearts", "Diamonds", "Clubs", "Spades"};
i i mod 13 i div 130 0 0
1 1 0
2 2 0
3 3 0
4 4 0
5 5 0
6 6 0
7 7 0
8 8 0
9 9 0
10 10 0
11 11 0
12 12 0
13 0 1
14 1 1
15 2 1
16 3 1
17 4 1
18 5 1
19 6 1
20 7 1
21 8 1
22 9 1
23 10 1
24 11 1
25 12 1
26 0 2
27 1 2
28 2 2
29 3 2
30 4 2
31 5 2
32 6 2
33 7 2
34 8 2
35 9 2
36 10 2
37 11 2
38 12 2
39 0 3
40 1 3
41 2 3
42 3 3
43 4 3
44 5 3
45 6 3
46 7 3
47 8 3
48 9 3
49 10 3
50 11 3
51 12 3
52 0 4
53 1 4
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void shuffle()
/* shuffle cards */void shuffle( Card * const wDeck ){ int i; /* counter */ int j; /* hold random value between 0 - 51 */ Card temp; /* temporary structure for swapping Cards */
/* loop through wDeck randomly swapping Cards */ for ( i = 0; i <= 51; i++ ) { j = rand() % 52; temp = wDeck[ i ]; wDeck[ i ] = wDeck[ j ]; wDeck[ j ] = temp; }}
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void deal()
/* deal cards */void deal(Card * wDeck ){ int i; /* counter */ for ( i = 0; i <= 51; i++ ) { printf( "%5s of %-8s%c", wDeck[ i ].face, wDeck[ i ].suit, ( i + 1 ) % 2 ? '\t' : '\n' ); }}
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output