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@Yuta_Nakamura_(Yuta Nakamura)

Daitell C Programming Practice Questions and Answers Chapter 10

Last updated at Posted at 2025-10-30
書籍

image.png

10.7: Using the program in Listing 10.9 (P.388), run a high-performance card shuffling and distribution simulation (shown in Listing 10.2 (P.374)).
source
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <time.h>

typedef struct bitCard{
  unsigned face : 4;
  unsigned suit : 2;
  unsigned color : 1;
}Card;

void fillDeck(Card *);
void shuffle(Card *);
void deal(Card *, char *[], char *[], char *[]);

int main()
{
    Card deck[52];
    char *face[] = {"Ace", "2", "3", "4", "5",
                    "6", "7", "8", "9", "10",
                    "Jack", "Queen", "King"};
    
    char *suit[] = {"Heart", "Diamond", "Club", "Spade"};

    char *color[] = {"red", "black"};

    // srand(time(NULL));

    fillDeck(deck);
    shuffle(deck);
    deal(deck, face, suit, color);

    getch();
    return 0;
}

void fillDeck(Card *wDeck)
{
    int i;

    for (i = 0; i <=51; i++)
    {
       wDeck[i].face = i % 13;
       wDeck[i].suit = i / 13;
       wDeck[i].color = i / 26;
    }
}

void shuffle(Card *wDeck)
{
    int i, j;
    Card tmp;

    for (i = 0; i <= 51; i++)
    {
       j = rand() % 52;
       tmp = wDeck[i];
       wDeck[i] = wDeck[j];
       wDeck[j] = tmp;
    }
}

void deal(Card *wDeck, char *wFace[], char *wSuit[], char *wColor[])
{
    int k1;
    //int k2;
   
    /*
    for (k1 = 0, k2 = k1 + 26; k1 <= 25; k1++, k2++)
    {
        printf("%10s : %8s of %-8s\t", 
            wColor[wDeck[k1].color], wSuit[wDeck[k1].suit], wFace[wDeck[k1].face]);

        printf("%10s : %8s of %-8s\n", 
            wColor[wDeck[k2].color], wSuit[wDeck[k2].suit], wFace[wDeck[k2].face]);
    }
    */
    for (k1 = 0; k1 <= 51; k1++)
    {
        printf("%6s : %8s of %-8s%c", 
            wColor[wDeck[k1].color], wSuit[wDeck[k1].suit], wFace[wDeck[k1].face], (k1 + 1) % 2 ? '\t' : '\n');
    }
}
10.8: char c, short s, int i, long lをメンバとする共用体integerを作り値を格納、かつ、中身を表示
C言語
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <time.h>
#include <signal.h>

typedef union integer{
    char c;
    short s;
    int i;
    long l;
}Integer;

int main()
{
    Integer a;
    Integer b;
    Integer c;
    Integer d;

    a.c = 'a';
    printf("1\n");
    printf("%c\n", a.c);
    printf("%d\n", a.i);
    printf("%ld\n", a.l);
    printf("%hd\n", a.s);
 
    b.s = (short)10;

    printf("2\n");
    printf("%c\n", b.c);
    printf("%d\n", b.i);
    printf("%ld\n", b.l);
    printf("%hd\n", b.s);
    
    c.i = 19;

    printf("3\n");
    printf("%c\n", c.c);
    printf("%d\n", c.i);
    printf("%ld\n", c.l);
    printf("%hd\n", c.s);
    
    d.l = (long)1000;
   
    printf("4\n");
    printf("%c\n", d.c);
    printf("%d\n", d.i);
    printf("%ld\n", d.l);
    printf("%hd\n", d.s);
    getch();
    return 0;
}
10.9: float f, double d, long double lをメンバとする共用体floatingPointを作り値を格納、かつ、中身を表示
C言語
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <time.h>
#include <signal.h>

typedef union floatingPoint{
   float f;
   double d;
   long double l;
}FloatingPoint;

int main()
{
    FloatingPoint a;
    FloatingPoint b;   
    FloatingPoint c;
  
    a.f = 4.0f;
    b.d = 5.0;
    c.l = 5.1L;

    printf("a\n");
    printf("%f\n", a.f);
    printf("%lf\n", a.d);
    printf("%Lf\n", a.l);

    printf("\nb\n");
    printf("%f\n", b.f);
    printf("%lf\n", b.d);
    printf("%Lf\n", b.l);

    printf("\nc\n");
    printf("%f\n", c.f);
    printf("%lf\n", c.d);
    printf("%Lf\n", c.l);

    getch();
    return 0;
}
10.10: 整数型変数を4ビット右にシフト
C言語
#include <stdio.h>
#include <conio.h>
#include <time.h>
#include <signal.h>
#include <string.h>
#include <ctype.h>

// ビット列を表示する関数
void printBitInt(int value)
{
    for (int i = 31; i >= 0; i--) {
        int bit = (value >> i) & 1;
        printf("%d", bit);
        if (i % 8 == 0 && i != 0) {
            printf(" "); // 8ビットごとにスペース
        }
    }
}

// 右シフトする関数
int shiftRight(int value, int n)
{
    return value >> n;
}

int main()
{
    int data = 64;

    printBitInt(data);
    printf("\n");

    data = shiftRight(data, 4);

    printBitInt(data);
    printf("\n");

    getch();
    return 0;
}
10.11: 4バイト整数マシンを使っている場合にリスト10.5(P.381)のプログラムを4バイト整数でも動くように改造
C言語
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <time.h>
#include <signal.h>
#include <string.h>
#include <ctype.h>

int main()
{
    unsigned x;

    //printf("%d\n", sizeof(unsigned));

    void displayBits(unsigned);

    printf("符号なし整数を入力してください\n");
    scanf("%u", &x);
 
    displayBits(x);

    getch();
    return 0;
}

void displayBits(unsigned value)
{
    unsigned c, displayMask = 1 << (sizeof(unsigned) * 8) - 1;
    
    printf("%8u = ", value);

    for (c = 1; c <= 32; c++)
    {
        putchar(value & displayMask ? '1' : '0');
        value <<= 1;

        if (c % 8 == 0)
        {
            putchar(' ');
        }
    }

    putchar('\n');
}
10.12: 2つの整数型引数numberとpowを受け取って、number * 2^(pow)を計算する関数power2を実装(^はべき乗)
C言語
#include <stdio.h>
#include <conio.h>
#include <ctype.h>

int power2(int, int);

void printBitInt(int number)
{
    int i;
    int size = sizeof(int) * 8; // 通常32ビット

    for (i = size - 1; i >= 0; i--) {
        printf("%d", (number >> i) & 1);
        if (i % 8 == 0) printf(" "); // 8ビットごとにスペース
    }
}

int main()
{
    int a = 4;

    printf("%d\n", a);

    printBitInt(a);
    printf("\n\n");
  
    a = power2(a, 1);
    printf("%d\n", a);
    printBitInt(a);

    getch();
    return 0;
}

int power2(int number, int power)
{
    return number << power;
}
10.13: キーボードから2つの文字を入力し、それらを2バイトの整数型変数にパック
C言語
#include <stdio.h>
#include <conio.h>

void packCharacters(char, char, unsigned short *);
void printBitsChar(char);
void printBitsShort(unsigned short);

int main()
{
    char first, second;
    unsigned short pack;

    printf("文字を2つ入力してください\n");
    scanf(" %c %c", &first, &second);  // 先頭に空白を入れて改行をスキップ

    printBitsChar(first);
    printf("\n");
    printBitsChar(second);
    printf("\n");

    packCharacters(first, second, &pack);

    return 0;
}

void packCharacters(char a, char b, unsigned short *p)
{
    *p = a;
    printBitsShort(*p);
    printf("\n");

    *p <<= 8;
    printBitsShort(*p);
    printf("\n");

    *p |= b;
    printBitsShort(*p);
    printf("\n");
}

void printBitsChar(char c)
{
    for (int i = 7; i >= 0; i--)
        printf("%d", (c >> i) & 1);
}

void printBitsShort(unsigned short s)
{
    for (int i = 15; i >= 0; i--)
        printf("%d", (s >> i) & 1);
}
10.14: 10.13のunsigned整数を受け取って、そこから2つの文字をアンパック
C言語
#include <stdio.h>

void packCharacters(char, char, unsigned short *);
void unpackCharacters(unsigned short, char *, char *);
void printBitsShort(unsigned short);
void printBitsChar(char);  // 追加

int main()
{
    char first, second;
    char a, b;
    unsigned short pack;

    printf("文字を2つ入力してください\n");
    scanf(" %c %c", &first, &second);  // 空白を追加してバッファ問題を回避

    printBitsChar(first);
    printf("\n");
    printBitsChar(second);
    printf("\n");

    printf("pack\n");
    packCharacters(first, second, &pack);

    printf("unpack\n");
    unpackCharacters(pack, &a, &b);
    printf("%c %c\n", a, b);

    getchar();  // getch() の代わり
    return 0;
}

void packCharacters(char a, char b, unsigned short *p)
{
    *p = a;
    *p <<= 8;
    *p |= b;
    printBitsShort(*p);
    printf("\n\n");
}

void unpackCharacters(unsigned short p, char *a, char *b)
{
    *a = (p >> 8) & 0xFF;
    *b = p & 0xFF;
}

void printBitsShort(unsigned short s)
{
    for (int i = 15; i >= 0; i--)
        printf("%d", (s >> i) & 1);
}

void printBitsChar(char c)
{
    for (int i = 7; i >= 0; i--)
        printf("%d", (c >> i) & 1);
}
10.15: 10.13のプログラムを4文字パックするように改造
C言語
#include <stdio.h>

void packCharacters(char, char, char, char, unsigned *);
void printBitsChar(char);
void printBitsInt(int);

int main()
{
    char first, second, third, forth;
    unsigned pack;

    printf("文字を4つ入力してください\n");
    scanf("%c %c %c %c", &first, &second, &third, &forth);

    printf("1つ目\n");
    printBitsChar(first);
    printf("\n");
 
    printf("2つ目\n");
    printBitsChar(second);
    printf("\n");
 
    printf("3つ目\n");
    printBitsChar(third);
    printf("\n");
   
    printf("4つ目\n");
    printBitsChar(forth);
    printf("\n\n");

    packCharacters(first, second, third, forth, &pack);
    getchar();  // getch() の代わり
    return 0;
}

void packCharacters(char a, char b, char c, char d, unsigned *p)
{
     printBitsInt(*p);
     printf("\n");
     *p = a;
     printBitsInt(*p);
     printf("\n");
     *p <<= 8;

     printBitsInt(*p);
     printf("\n");
     *p |= b;
     printBitsInt(*p);
     printf("\n");
     *p <<= 8;

     printBitsInt(*p);
     printf("\n");
     *p |= c;
     printBitsInt(*p);
     printf("\n");
     *p <<= 8;
    
     printBitsInt(*p);
     printf("\n");
     *p |= d;
     printBitsInt(*p);
     printf("\n");
}

void printBitsChar(char c)
{
    for (int i = 7; i >= 0; i--)
        printf("%d", (c >> i) & 1);
}

void printBitsInt(int number)
{
    int i;
    int size = sizeof(int) * 8; // 通常32ビット

    for (i = size - 1; i >= 0; i--) {
        printf("%d", (number >> i) & 1);
        if (i % 8 == 0) printf(" "); // 8ビットごとにスペース
    }
}
10.16: Modify the program in Exercise 10.14 to unpack 4 characters(The mask required to unpack each character is created by shifting the mask variable, which has a value of 255, left by 8 bits as many times as necessary)
source
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

void packCharacters(char, char, char, char, unsigned *);
void unpackCharacters(unsigned, char *, char *, char *, char *);
void printBitsChar(char);
void printBitsInt(int);

int main()
{
    char first, second, third, forth;
    unsigned pack;

    printf("please input four characters\n");
    scanf("%c %c %c %c", &first, &second, &third, &forth);

    printf("first\n");
    printBitsChar(first);
    printf("\n");
 
    printf("second\n");
    printBitsChar(second);
    printf("\n");
 
    printf("third\n");
    printBitsChar(third);
    printf("\n");
   
    printf("fourth\n");
    printBitsChar(forth);
    printf("\n\n");

    packCharacters(first, second, third, forth, &pack);
    printf("Pack is complete\n");

    printf("Unpack it\n");
    unpackCharacters(pack, &first, &second, &third, &forth);

    printf("%c %c %c %c\n", first, second, third, forth);
    getch();
    return 0;
}

void packCharacters(char a, char b, char c, char d, unsigned *p)
{
     printBitsInt(*p);
     printf("\n");
     *p = a;
     printBitsInt(*p);
     printf("\n");
     *p <<= 8;

     printBitsInt(*p);
     printf("\n");
     *p |= b;
     printBitsInt(*p);
     printf("\n");
     *p <<= 8;

     printBitsInt(*p);
     printf("\n");
     *p |= c;
     printBitsInt(*p);
     printf("\n");
     *p <<= 8;
    
     printBitsInt(*p);
     printf("\n");
     *p |= d;
     printBitsInt(*p);
     printf("\n");
}

void unpackCharacters(unsigned pack, char *a, char *b, char *c, char *d)
{
     unsigned mask = 255;
     unsigned tmp;

     printBitsInt(pack);
     printf("\n");
     tmp = pack & (mask << (3 * 8));
     *a = tmp >> (3 * 8);

     tmp = pack & (mask << (2 * 8));
     *b = tmp >> (2 * 8);

     tmp = pack & (mask << (1 * 8));
     *c =  tmp >> (1 * 8);

     *d = pack & mask;   
}

void printBitsChar(char c)
{
    for (int i = 7; i >= 0; i--)
        printf("%d", (c >> i) & 1);
}

void printBitsInt(int number)
{
    int i;
    int size = sizeof(int) * 8;

    for (i = size - 1; i >= 0; i--) {
        printf("%d", (number >> i) & 1);
        if (i % 8 == 0) printf(" ");
    }
}
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