第四次实验

task1-1

#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、int型数据a,在内存中是连续存放的，每个元素占用4个内存单元；

2、char型数据b，在内存中是连续存放的，每个元素占用1个内存字节单位；

3、书著名a对应的数组名，和&a[0]是一样的，数组名b对应的值，和&b[0]是一样的

task1-2

#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;
    
    printf("sizeof(int) = %d\n",sizeof(int));
    printf("sizeof(char) = %d\n",sizeof(char));
    printf("\n");
    
    //输出二维数组中每个元素的地址、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");
    
    //输出二维数组中每个元素的地址、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、int型二维数组a，在内存中是“按行连续存放”的，每个元素占用4个内存字节单元；

2、char型二维数组b，在内存中是“按行连续存放”的，每个元素占用1个内存字节单元；

task2、

#include<stdio.h>
int days_of_year(int year,int month,int day);//函数声明
int main()
{
int year,month,day;
int days;
while(scanf("%d%d%d",&year,&month,&day)!=EOF)//按下Ctrl+Z终止
{
days=days_of_year(year,month,day);//函数调用
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 sum=0,i,a[]={0,31,28,31,30,31,30,31,31,30,31,30,31};
if(year % 400 == 0 || year % 100 != 0 && year % 4 == 0)
 {a[2]++;}
for(i=1;i<month;i++)
{
sum+=a[i];
}
sum+=day;
return sum;
}
//函数定义
//补足函数days_of_year的定义
//xxx

 

task3、

#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)
{ double sum=0;
  int i;
  for(i=0;i<n;i++)
   sum+=x[i];
  return sum/n;
}
void sort(int a[],int n)
{
    int i,j,index;
    int temp;
    int m;
    for(i = 0; i < n-1; i++){
            index=i;
        for(j = i + 1;j < n; j++){ //寻找最小值
            if(a[index]<a[j]) //a[i]若不是最小
                index=j;        //记录最小值下标
        }
         if(index !=i)    //最小值和第i个记录进行互换
        {
            temp=a[i];
            a[i]=a[index];
            a[index]= temp; //a[i]的值赋给被交换的位置
        }
 
    }
}
//计算整型数组x中n个元素均值，并返回
//补足函数average()实现
//×××

//对整型数组x中的n个元素降序排序
//补足函数sort()实现
//××x

task4

#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[80];
    int  i=1,k,j=0;
    
    while(x!=0)
    {
        i=x%n;
        a[j++]=i;
        x=x/n;
    }
    
    for(k=j-1;k>=0;k--)
    {
        if(a[k]>9&&a[k]<16)
            printf("%c",a[k]-10+'A');
        else
            printf("%d",a[k]);
    }
    
    printf("\n");
        
}

task5

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

task6

#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;
  
 
    printf("original views:\n");
    printf("views1:%s\n", views1);
    printf("views2:%s\n", views2);
 
    printf("\n");
 
    for (i = 0; i < N; i++)
    {
        views1[20] = views1[i];
        views1[i] = views2[i];
        views2[i] = views1[20];
    }
 
    printf("swapping...\n");
 
    printf("views1:%s\n", views1);
    printf("views2:%s\n", views2);
 
    return 0;
}

task7

#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;
    char c[80];
    for(i=0;i<n-1;i++)
    {
        for(j=0;j<n-i-1;j++)
        {
            if(strcmp(str[j],str[j+1])>0)
            {
            strcpy(c,str[j]);
            strcpy(str[j],str[j+1]);
            strcpy(str[j+1],c);
            }
        }
    }
}