实验4 数组

Task 1

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.是连续存放的，每个元素占4个内存字节单元

2.是连续存放的，每个元素占1个内存字节单元

3.一样，一样

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b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

2.是，1个

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是这一年中的第%d天.\n\n", year, month, day, days);
    }
    return 0;
}
int days_of_year(int year, int month, int day)
{
    int n=0;
    int i;
    int x[13] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };
    if ((year % 4 == 0 && year % 100 != 0) || (year % 400 == 0))
        x[2] = 29;
    for (i = 1; i < month; i++)
        n = n + x[i];
    return n + day;
}

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");
}

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

void sort(int x[], int n)
{
    int i,j,t;
    for(j=0;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);
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)
{
    int a[1000];
    int i;
    for (i = 0;x!=0; i++)
    {
        a[i] = x % n;
        x = x / n;
    }
    for (i = i - 1; i >= 0; i--)
    {
        if (a[i] == 10)
            printf("%c", 'A');
        else if (a[i] == 11)
            printf("%c", 'B');
        else if (a[i] == 12)
            printf("%c", 'C');
        else if (a[i] == 13)
            printf("%c", 'D');
        else if (a[i] == 14)
            printf("%c", 'F');
        else if (a[i] == 15)
            printf("%c", 'E');
        else if (a[i] <10)
            printf("%d", a[i]);
    }
    printf("\n");
}

Task 5

#include<stdio.h>
#define N 30
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 
#include <string.h>
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);
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 t[10];
    for(i=0;i<n-1;i++)
        for(j=0;j<n-i-1;j++)
            if (strcmp(str[j], str[j + 1]) > 0)
            {
                strcpy(t, str[j]);
                strcpy(str[j], str[j + 1]);
                strcpy(str[j + 1], t);
            }
}