明解C语言入门篇（第5章练习题）

5.1

#include

int main(void)
{
    int i;
    int v[5];

    for (i = 0; i < 5; i++)
        v[i] = i;
    for (i = 0; i < 5; i++)
        printf("v[%d] = %d\n", i, v[i]);

    return 0;
}

5.2

#include

int main(void)
{
    int i;
    int v[5];

    for (i = 0; i < 5; i++)
        v[i] = 5 - i;
    for (i = 0; i < 5; i++)
        printf("v[%d] = %d\n", i, v[i]);

    return 0;
}

5.3

#include

int main(void)
{
    int i;
    int v[5] = {5, 4, 3, 2, 1};

    for (i = 0; i < 5; i++)
        printf("v[%d] = %d\n", i, v[i]);

    return 0;
}

5.4

#include

int main(void)
{
    int i;
    int a[5] = {17, 23, 36};
    int b[5];

    for (i = 0; i < 5; i++)
        b[i] = a[4 - i];
    puts("  a    b");
    puts("---------");
    for (i = 0; i < 5; i++)
        printf("%4d%4d\n", a[i], b[i]);

    return 0;
}

5.5

#include

#define NUMBER 7

int main(void)
{
    int i;
    int x[NUMBER];

    for (i = 0; i < NUMBER; i++)
    {
        printf("x[%d]: ", i);
        scanf("%d", &x[i]);
    }
    for (i = 0; i < NUMBER / 2; i++)
    {
        int temp = x[i];
        x[i] = x[NUMBER - 1 - i];
        x[NUMBER - 1 - i] = temp;
    }
    puts("倒序排列了。");
    for (i = 0; i < 7; i++)
        printf("x[%d] = %d\n", i, x[i]);

    return 0;
}

5.6

#include

int main(void)
{
    double a;
    int b;

    a = b = 1.5;
    printf("%.1f %d", a, b);

    return 0;
}

5.7

#include

#define NUMBER 100

int main(void)
{
    int i, j;
    int num, n;
    int a[NUMBER];

    printf("请输入数据个数: ");
    do{
        scanf("%d", &n);
        if (n < 1 || n > NUMBER)
            printf("请输入1~%d的数: ", NUMBER);
    }while (n < 1 || n > NUMBER);
    for (i = 0; i < n; i++)
    {
        printf("%d号: ", i + 1);
        scanf("%d", &num);
        a[i] = num;
    }
    printf("{");
    for (j = 0; j < n; j++){
        if (j == n - 1)
            printf("%d", a[j]);
        else
            printf("%d, ", a[j]);
    }
    printf("}");
    
    return 0;
}

5.8

#include

#define NUMBER 80

int main(void)
{
    int i, j;
    int num;
    int tensu[NUMBER];
    int bunpu[11] = {0};

    printf("请输入学生人数: ");
    do{
        scanf("%d", &num);
        if (num < 1 || num > NUMBER)
            printf("请输入1-%d的数: ", NUMBER);
    }while (num < 1 || num > NUMBER);
    printf("请输入%d人的分数。\n", num);
    for (i = 0; i < num; i++)
    {
        printf("%2d号: ", i + 1);
        do{
            scanf("%d", &tensu[i]);
            if (tensu[i] < 1 || tensu[i] > 100)
                printf("请输入1~100的数: ");
        }while (tensu[i] < 1 || tensu[i] > 100);
        bunpu[tensu[i] / 10]++;
    }
    puts("\n---分布图---");
    for (i = 0; i <= 9; i++)
    {
        printf("%3d - %3d:", i * 10, i * 10 + 9);
        for (j = 0; j < bunpu[i]; j++)
            putchar('*');
        putchar('\n');
    }
    printf("      100:");
    for (j = 0; j < bunpu[10]; j++)
        putchar('*');
    putchar('\n');

    return 0;
}

5.9

#include

#define NUMBER 80

int main(void)
{
    int i, j, max;
    int num;
    int tensu[NUMBER];
    int bunpu[11] = {0};

    printf("请输入学生人数: ");
    do{
        scanf("%d", &num);
        if (num < 1 || num > NUMBER)
            printf("请输入1-%d的数: ", NUMBER);
    }while (num < 1 || num > NUMBER);
    printf("请输入%d人的分数。\n", num);
    for (i = 0; i < num; i++)
    {
        printf("%2d号: ", i + 1);
        do{
            scanf("%d", &tensu[i]);
            if (tensu[i] < 1 || tensu[i] > 100)
                printf("请输入1~100的数: ");
        }while (tensu[i] < 1 || tensu[i] > 100);
        bunpu[tensu[i] / 10]++;
    }
    puts("\n---分布图---");
    max = bunpu[0];
    for (i = 1; i < 11; i++)
    {
        if (max < bunpu[i])
            max = bunpu[i];
    }
    for (j = max; j > 0; j--)
    {
        for (i = 0; i < 11; i++)
        {
            if (bunpu[i] >= j)
                printf(" *  ");
            else
                printf("    ");
        }
        putchar('\n');
    }
    putchar('\n');
    printf("---------------------------------------------\n");
    for (j = 0; j <= 100; j += 10)
    {
        printf(" %d ", j);
    }

    return 0;
}

5.10

#include

int main(void)
{
    int i, j, k;
    int a[4][3];
    int b[3][4];
    int c[4][4];

    printf("请输入4行3列矩阵的元素的值:。\n");
    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < 3; j++)
        {
            printf("a[%d][%d]: ", i, j);
            scanf("%d", &a[i][j]);
        }
    }
     printf("请输入3行4列矩阵的元素的值:。\n");
    for (i = 0; i < 3; i++)
    {
        for (j = 0; j < 4; j++)
        {
            printf("b[%d][%d]: ", i, j);
            scanf("%d", &b[i][j]);
        }
    }
    for (i = 0; i < 4; i++)   /* 计算矩阵的乘积 */
    {
        for (j = 0; j < 4; j++)
        {
            c[i][j] = 0;
            for (k = 0; k < 3; k++)
            {
                c[i][j] += a[i][k] + b[k][j];
            }
        }
    }
    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < 4; j++)
        {
            printf("c[%d][%d] = %d\n", i, j, c[i][j]);
        }
    }

    return 0;
}

5.11

#include

int main(void)
{
    int i, j;
    int a[6][2];
    int b[6];  /* 学生的总分 */
    int c[2];  /* 课程的总分 */
    double d[2];   /* 课程的平均分 */
    double e[6];   /* 学生的平均分 */

    for (i = 0; i < 6; i++)
    {
        for (j = 0; j < 2; j++)
        {
            printf("请输入第%d位同学第%d门的成绩: ", i + 1, j + 1);
            scanf("%d", &a[i][j]);
        }
    }
    for (i = 0; i < 2; i++)
    {
        c[i] = 0;
    }
    for (i = 0; i < 6; i++)
    {
        b[i] = 0;
    }
    /* 计算各门课程的总分和平均分 */
    for (i = 0; i < 2; j++)
    {
        for (j = 0; j < 6; j++)
        {
            c[i] += a[j][i];
        }
        d[i] = c[i] / 6;
        printf("第%d门课程的总分为%d, 平均分为%.2f\n",i + 1, c[i], d[i]);
    }
    /* 计算每位学生的总分和平均分 */
    for (i = 0; i < 6; i++)
    {
        for (j = 0; j < 2; j++)
        {
            b[i] += a[i][j];
        }
        e[i] = b[i] / 2;
        printf("第%d位学生的总分为%d, 平均分为%.2f\n",i + 1, b[i], e[i]);
    }

    return 0;
}

5.12

#include

int main(void)
{
    int i, j, k;
    int tensu[2][4][3] = {{{91, 63, 78}, {67, 72, 46}, {89, 34, 53}, {32, 54, 34}},
                          {{97, 67, 82}, {73, 43, 46}, {97, 56, 21}, {85, 46, 35}}};
    int sum[4][3];

    for (i = 0; i < 4; i++)
    {
        for (j = 0; i < 3; j++)
        {
            sum[i][j] = 0;
            for (k = 0; k < 2; k++)
            {
                sum[i][j] += tensu[k][i][j];
            }
        }
    }
    for (k  = 0; k < 2; k++)
    {
        printf("第%d次考试的分数", k + 1);
        for (i = 0; i < 4; i++)
        {
            for (j = 0; j < 3; j++)
            {
                printf("%4d", tensu[k][i][j]);
            }
            putchar('\n');
        }
    }
    puts("总分");
    for (i = 0; i < 4; i++)
    {
        for (j = 0; j < 3; j++)
        {
            printf("%4d", sum[i][j]);
        }
        putchar('\n');
    }

    return 0;
}