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: %c\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.连续，4个字节

2.连续，1个字节

3.都一样

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，4个字节单元

2.是，1个字节单元

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("%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 s=0,i,days;
    int a[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};
    
    for(i=0;i<month;i++)
    {
        s=s+a[i];
    }
    
    if(year%4==0&&year%100!=0||year%400==0)
    s=s+1;
    days=s+day;
    return days;
}

 

task.3

#include<stdio.h>
#define N 5

//函数声明
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;
}

// 函数定义
// 输入n个整数保存到整型数组x中
void input(int x[], int n)
{
    int i;
    
    for(i=0; i<n; ++i)
    scanf("%d", &x[i]);
}

// 输出整型数组x中n个元素
void output(int x[], int n)
{
    int i;
    
    for(i=0; i<n; ++i)
    printf("%d ", x[i]);
    
    printf("\n");
}

// 计算整型数组x中n个元素均值，并返回
double average(int x[],int n)
{
    int i;
    double s=0;
    for(i=0;i<=n;i++)
    {
        s=s+x[i];
    }
    return (s/n);
}

// 对整型数组x中的n个元素降序排序
void sort(int x[], int n)
{
    int i,j,t;
    for(j=1;j<=n-1;j++)
    {
        for(i=0;i<=n-j-1;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); // 函数声明

int main()
{
    int x;
    
    printf("输入一个十进制整数: ");
    scanf("%d", &x);
    
    dec2n(x, 2); // 函数调用: 把x转换成二进制输出
    dec2n(x, 8); // 函数调用: 把x转换成八进制输出
    dec2n(x, 16); // 函数调用: 把x转换成十六进制输出
    
    return 0;
}

// 函数定义 
// 功能: 把十进制数x转换成n进制，打印输出
void dec2n(int x, int n)
{
    int a[80];
    int i,j;
    for(i=0;i<=80;i++)
    {
        if(x/n!=0)
        {
            a[i]=x%n;
            x=x/n;
        }
        else
        {
            a[i]=x;
            break;
        }
            
    }
    for(j=i;j>=0;j--)
    {
        if(n==16&&a[j]>=10)
        {
            switch(a[j]%10)
            {
                case 0: printf("A");break;
                case 1: printf("B");break;
                case 2: printf("C");break;
                case 3: printf("D");break;
                case 4: printf("E");break;
                case 5:    printf("F");break;
            }
        }
        
        else
        printf("%d",a[j]); 
    }    
    
    printf("\n");
}

 

task.5

#include<stdio.h>
#define N 20
int main()
{
    int a[N][N];
    int n;
    int i, j, k;
    printf("Enter n: ");
    while(scanf("%d",&n)!=EOF)
    {
         for (i = 0; i < n; i++)
         for (j = 0; j < n; j++)
            if(i<j)
               a[i][j]=i+1;
            else
               a[i][j]=j+1;
    for (i = 0; i < n; i++)
    {
        for (j = 0; j < n; j++)
            printf("%d ", a[i][j]);
            printf("\n");
    }
    printf("\nEnter n: ");
    }
   
    return 0;
}

 

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.";
    
    char temp;
    int i = 0;
    printf("original views:\n");
    printf("views1: %s\n",views1);
    printf("views2: %s\n",views2);
    while(views1[i]!='\0')
    {
        temp = views1[i];
        views1[i] = views2[i];
        views2[i] = temp;
        i++;
    }
    printf("\nswapping...\n");
    printf("views1: %s\n",views1);
    printf("views2: %s\n",views2);
    
    return 0;
}

task.7

#include <stdio.h>
#include <string.h>

#define N 5 
#define M 20

void bubble_sort(char str[][M], int n); // 函数声明

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); // 函数调用
    
    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;
    char temp[M];
    for(j=0;j<n;j++)
    {
        for(i=0;i<n-1;i++)
        {
            if(strcmp(str[i],str[i+1])>0)
            {
               strcpy(temp,str[i]);
               strcpy(str[i],str[i+1]);
               strcpy(str[i+1],temp);
             }
        }
        
    }
        
}