实验四

task-1.1

#include<stdio.h>
#define N 4

int main()
{
    int a[N] = { 2,0,2,2 };
    char b[N] = { '2','0','2','2' };
    int i;

    printf("sizeof(int)=%d\n", sizeof(int));
    printf("sizeof(char)=%d\n", sizeof(char));
    printf("\n");

    //输出数组a中每个元素的地址、值
    for (i = 0; i < N; ++i)
        printf("%p;%d\n", &a[i], a[i]);
    printf("\n");

    //输出数组b中每个元素的地址、值
    for (i = 0; i < N; ++i)
        printf("%p:%c\n", &b[i], b[i]);
    printf("\n");

    //输出数组名a和b对应的值
    printf("a=%p\n", a);
    printf("b=%p\n", b);

    return 0;
}

1.是，每个元素占4个内存字节单元

2.是，每个元素占1个内存字节单元

3.是，是

task-1.2

#include <stdio.h> 
#define N 2 
#define M 3 
int main()
{
    int a[N][M] = { {1, 2, 3}, {4, 5, 6} };
    char b[N][M] = { {'1', '2', '3'}, {'4', '5', '6'} };
    int i, j;

    // 输出二维数组a中每个元素的地址和值 
    for (i = 0; i < N; ++i)
        for (j = 0; j < M; ++j)
            printf("%p: %d\n", &a[i][j], a[i][j]);
    printf("\n");

    // 输出二维数组a中每个元素的地址和值 
    for (i = 0; i < N; ++i)
        for (j = 0; j < M; ++j)
            printf("%p: %c\n", &b[i][j], b[i][j]);

    return 0;
}

1.是，每个元素占4个内存字节单元

2.是，每个元素占1个内存字节单元

task-2

#include <stdio.h> 
int days_of_year(int year, int month, int day);
int main()
{
    int year, month, day;
    int days;
    while (scanf_s("%d%d%d", &year, &month, &day) != EOF)
    {
        days = days_of_year(year, month, day);
        printf("%4d-%02d-%02d是这一年的第%d天.\n\n", year, month, day, days);
    }
    return 0;
}
int days_of_year(int year, int month, int day)
{
    int i;
    int mon[] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };
    int s = 0;
    for (i = 1; i < month; ++i)
        s = s + mon[i];
    s = s + day;
    if ((year % 4 == 0 && year % 100 != 0 || year % 400 == 0) && month >= 3)
        s++;
    return s;
}

task-3

#include <stdio.h>
#define N 5
void input(int x[], int n);
void output(int x[], int n);
double average(int x[], int n);
void sort(int x[], int n);

int main()
{
    int scores[N];
    double ave;
    
    printf("录入%d个分数:\n", N);
    input(scores, N);
    
    printf("\n输出课程分数: \n");
    output(scores, N);
    
    printf("\n课程分数处理: 计算均分、排序...\n");
    ave = average(scores, N);
    sort(scores, N);
    
    printf("\n输出课程均分: %.2f\n", ave);
    printf("\n输出课程分数(高->低):\n");
    output(scores, N);
    
    return 0;
}

void input(int x[], int n)
{
    int i;
    for(i=0; i<n; ++i)
        scanf("%d", &x[i]);
}
void output(int x[],int n)
{
    int i;
    for(i=0; i<n; ++i)
        printf("%d ", x[i]);
    
    printf("\n");
}

double average(int x[],int n)
{
    int i,s=0;
    double ave;
    for(i=0;i<n;++i)
        s+=x[i];
    ave=(double)s/n;
    
    return ave;
}

void sort(int x[],int n)
{
    int i,j,t;
    for(j=0;j<n-1;j++)
        for(i=n-1;i>0;--i)
        {
            if(x[i]>x[i-1])
            {
                t=x[i];
                x[i]=x[i-1];
                x[i-1]=t;
                
            }
            
        }
}

task-4

#include <stdio.h>
void dec2n(int x, int n);
int main()
{
    int x;
    
    printf("输入一个十进制整数: ");
    scanf("%d", &x);
    
    dec2n(x, 2);
    dec2n(x, 8);
    dec2n(x, 16);
    
return 0;
}

void dec2n(int x,int n)
{
        char a[50];
        int i=0,j;
        while(x!=0)
        {
            if(x%n>=10)
                a[i]=x%n+55;
            else
                a[i]=x%n+48;
            x=x/n;
            i++;
        }
        
        for(j=i-1;j>=0;j--)
            printf("%c",a[j]);
    
    printf("\n");
}

task-5

#include<stdio.h>
#include<stdlib.h>
#define N 100
void fun(int x[N][N], int n);
int main()
{
    int n, i, j, a[N][N];
    printf("Enter n:");
    while (scanf_s("%d", &n) != EOF)
    {
        fun(a, n);
        for (i = 1; i <= n; i++)
        {
            for (j = 1; j <= n; j++)
                printf("%d ", a[i][j]);
            printf("\n");
        }
        printf("\nEnter n:");
    }
}
void fun(int x[N][N], int n)
{
    int i, j;
    for (i = 1; i <= n; i++)
        for (j = 1; j <= n; j++)
            if (i <= j)
                x[i][j] = i;
            else
                x[i][j] = j;
}

task-6

#include <stdio.h>
#define N 80
int main()
{
    char views1[N] = "hey, c, i hate u.";
    char views2[N] = "hey, c, i love u.";
    int i, j;
    char t;

    printf("original views:\n");
    printf("views1:");
    for (i = 0; i < N; i++)
        printf("%c", views1[i]);
    printf("\nviews2:");
    for (j = 0; j < N; j++)
        printf("%c", views2[j]);
    printf("\n");

    printf("\nswapping...\n\n");

    for (i = 0; i < N; i++)
        for (j = 0; j < N; j++)
            if (i == j)
            {
                t = views1[i];
                views1[i] = views2[j];
                views2[j] = t;
            }
    printf("views1:");
    for (i = 0; i < N; i++)
        printf("%c", views1[i]);
    printf("\nviews2:");
    for (j = 0; j < N; j++)
        printf("%c", views2[j]);
    printf("\n");

    return 0;
}

task-7

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<string.h>
#define N 5
#define M 20
void bubble_sort(char str[][M], int n);
int main()
{
    char name[][M] = { "Bob","Bill","Joseph","Taylor","George" };
    int i;
    printf("输出初始名单:\n");
    for (i = 0; i < N; i++)
        printf("%s\n", name[i]);
    printf("\n排序中...\n");
    bubble_sort(name, N);
    printf("\n按字典序输出名单:\n");
    for (i = 0; i < N; i++)
        printf("%s\n", name[i]);
    return 0;
}
void bubble_sort(char str[][M], int n)
{
    int i, j, k;
    char t[M];
    for (i = 0; i < N - 1; i++)
    {
        for (j = 0; j < N - 1 - i; j++)
        {
            k = strcmp(str[j], str[j + 1]);
            if (k > 0)
            {
                strcpy(t, str[j]);
                strcpy(str[j], str[j + 1]);
                strcpy(str[j + 1], t);
            }
        }
    }
}