实验4

task1_1.c

#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");
    
    for(i=0;i<N;++i)
        printf("%p:%d\n",&a[i],a[i]);
    
    printf("\n");
    
    for(i=0;i<N;++i)
        printf("%p:%c\n",&b[i],b[i]);
    
    printf("\n");
    
    printf("a=%p\n",a);
    printf("b=%p\n",b);
    
    return 0;
}

1.是，每个元素占用4个内存字节单元。

2.是，每个元素占用1个内存单元。

3.是；是

task1_2.c

#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;
    for (i = 0; i < N; ++i)
        for (j = 0; j < M; ++j)
            printf("%p: %d\n", &a[i][j], a[i][j]);
    
    printf("\n");
    
    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，每个元素占用4个内存字节单元。

2.是，每个元素占用1个内存字节单元。

task2.c

#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 d=0,i;
    if((year%4==0&&year%100!=0)||year%400==0)
    {
        int a[12]={31,29,31,30,31,30,31,31,30,31,30,31};
        for(i=0;i<month-1;i++)
            d+=a[i];
        d+=day;
    }
    else
    {
        int a[12]={31,28,31,30,31,30,31,31,30,31,30,31};
        for(i=0;i<month-1;i++)
            d+=a[i];
        d+=day;
    }
    return d;
}

task3.c

#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;
                
            }
            
        }
}
    

task4.c

#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");
}

task5.c

#include<stdio.h>
#define N 50
#define M 50

int main()
{
    int n,i,j,x[N][M];
    printf("Enter n: ");
    while(scanf("%d",&n)!=EOF)
    {
        for(i=0;i<=n-1;i++)
        {
            for(j=0;j<=n-1;j++)
            {
                if(i<=j)
                    x[i][j]=i+1;
                else
                    x[i][j]=j+1;
                printf("%4d",x[i][j]);
            }
            printf("\n");
        }
        printf("\nEnter n: ");
    }
    return 0;
}

task6.c

#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;
}

task7.c

#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 t;
    char temp[M];
    for(t=0;t<N-1;t++)
        for(n=0;n<N;n++)
            if(strcmp(str[n],str[n+1])>0)
            {
                strcpy(temp,str[n]);
                strcpy(str[n],str[n+1]);
                strcpy(str[n+1],temp);
                
            }
}

字符串的函数很好用！