实验5

实验一

代码:

#include <stdio.h>
#define N 5

void input(int x[], int n);
void output(int x[], int n);
void find_min_max(int x[], int n, int *pmin, int *pmax);

int main() {
    int a[N];
    int min, max;

    printf("录入%d个数据:\n", N);
    input(a, N);
#include <stdio.h>
#define N 5

void input(int x[], int n);
void output(int x[], int n);
int *find_max(int x[], int n);

int main() {
    int a[N];
    int *pmax;

    printf("录入%d个数据:\n", N);
    input(a, N);

    printf("数据是: \n");
    output(a, N);

    printf("数据处理...\n");
    pmax = find_max(a, N);

    printf("输出结果:\n");
    printf("max = %d\n", *pmax);

    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");
}

int *find_max(int x[], int n) {
    int max_index = 0;
    int i;

    for(i = 0; i < n; ++i)
        if(x[i] > x[max_index])
            max_index = i;
    
    return &x[max_index];
}

 



    printf("数据是: \n");
    output(a, N);

    printf("数据处理...\n");
    find_min_max(a, N, &min, &max);

    printf("输出结果:\n");
    printf("min = %d, max = %d\n", min, max);

    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");
}

void find_min_max(int x[], int n, int *pmin, int *pmax) {
    int i;
    
    *pmin = *pmax = x[0];

    for(i = 0; i < n; ++i)
        if(x[i] < *pmin)
            *pmin = x[i];
        else if(x[i] > *pmax)
            *pmax = x[i];
}

 

 

问题1:find_min_max的作用是将最大值的地址赋给pmax,最小值的地址赋给pmin,pmin和pmax都·指向x[0]

问题2:find_max的功能是返回最大值的地址;可以写成以下代码

 

实验二

代码:

#include <stdio.h>
#include <string.h>
#define N 80

int main() {
    char s1[N] = "Learning makes me happy";
    char s2[N] = "Learning makes me sleepy";
    char tmp[N];

    printf("sizeof(s1) vs. strlen(s1): \n");
    printf("sizeof(s1) = %d\n", sizeof(s1));
    printf("strlen(s1) = %d\n", strlen(s1));

    printf("\nbefore swap: \n");
    printf("s1: %s\n", s1);
    printf("s2: %s\n", s2);

    printf("\nswapping...\n");
    strcpy(tmp, s1);
    strcpy(s1, s2);
    strcpy(s2, tmp);

    printf("\nafter swap: \n");
    printf("s1: %s\n", s1);
    printf("s2: %s\n", s2);

    return 0;
}

问题:s1的大小是23;sizeof(s1)计算的是s1所占字节数;strlen(s1)统计的是s1的字符串长度;不能,定义了一个数组后不能直接赋值,可以用strcpy函数;内容已交换;

#include <stdio.h>
#include <string.h>
#define N 80

int main() {
    char *s1 = "Learning makes me happy";
    char *s2 = "Learning makes me sleepy";
    char *tmp;

    printf("sizeof(s1) vs. strlen(s1): \n");
    printf("sizeof(s1) = %d\n", sizeof(s1));
    printf("strlen(s1) = %d\n", strlen(s1));

    printf("\nbefore swap: \n");
    printf("s1: %s\n", s1);
    printf("s2: %s\n", s2);

    printf("\nswapping...\n");
    tmp = s1;
    s1 = s2;
    s2 = tmp;

    printf("\nafter swap: \n");
    printf("s1: %s\n", s1);
    printf("s2: %s\n", s2);

    return 0;
}

问题:存放的是字符串 Learning makes me happy 在内存中的地址;sizeof(s1) 计算的是字符串 Learning makes me happy 在内存中的地址名 的大小;strlen(s1) 统计的是字符串 Learning makes me happy的长度;能替换,

char *s1; s1 = "Learning makes me happy";定义了一个字符指针并让它指向一个字符串常量,由于s1只代表地址,所以不能修改字符串常量的内容,而2.1中是定义了一个字符数组,并将字符串复制到数组中,数组中的字符串可以被修改;交换的是两个字符串的地址;没有交换;

 

 

实验三

代码:

#include <stdio.h>

int main() {
    int x[2][4] = {{1, 9, 8, 4}, {2, 0, 4, 9}};
    int i, j;
    int *ptr1;     // 指针变量,存放int类型数据的地址
    int(*ptr2)[4]; // 指针变量,指向包含4个int元素的一维数组

    printf("输出1: 使用数组名、下标直接访问二维数组元素\n");
    for (i = 0; i < 2; ++i) {
        for (j = 0; j < 4; ++j)
            printf("%d ", x[i][j]);
        printf("\n");
    }

    printf("\n输出2: 使用指针变量ptr1(指向元素)间接访问\n");
    for (ptr1 = &x[0][0], i = 0; ptr1 < &x[0][0] + 8; ++ptr1, ++i) {
        printf("%d ", *ptr1);

        if ((i + 1) % 4 == 0)
            printf("\n");
    }
                         
    printf("\n输出3: 使用指针变量ptr2(指向一维数组)间接访问\n");
    for (ptr2 = x; ptr2 < x + 2; ++ptr2) {
        for (j = 0; j < 4; ++j)
            printf("%d ", *(*ptr2 + j));
        printf("\n");
    }

    return 0;
}

问题:ptr1存放地址,ptr2指向数组

 

实验四

代码:

#include <stdio.h>
#define N 80

void replace(char *str, char old_char, char new_char); // 函数声明

int main() {
    char text[N] = "Programming is difficult or not, it is a question.";

    printf("原始文本: \n");
    printf("%s\n", text);

    replace(text, 'i', '*'); // 函数调用 注意字符形参写法,单引号不能少

    printf("处理后文本: \n");
    printf("%s\n", text);

    return 0;
}

// 函数定义
void replace(char *str, char old_char, char new_char) {
    int i;

    while(*str) {
        if(*str == old_char)
            *str = new_char;
        str++;
    }
}

问题:将文本中的i替换为*;可以

 

实验五:

代码:

 

#include <stdio.h>
#define N 80

char *str_trunc(char *str, char x);

int main() {
    char str[N];
    char ch;

    while(printf("输入字符串: "), gets(str) != NULL) {
        printf("输入一个字符: ");
        ch = getchar();

        printf("截断处理...\n");
        str_trunc(str, ch);         // 函数调用

        printf("截断处理后的字符串: %s\n\n", str);
        getchar();
    }

    return 0;
}

char *str_trunc(char *str,char x){
    char *p=str;
    while(*p!='\0'){
        if(*p==x){
        
        *p='\0';
        break;}
        p++;
        
    }
    
    
    
} 

 

问题:使回车不被读取

 

实验六

代码:

#include <stdio.h>
#include <string.h>
#define N 5

int check_id(char *str); // 函数声明

int main()
{
    char *pid[N] = {"31010120000721656X",
                    "3301061996X0203301",
                    "53010220051126571",
                    "510104199211197977",
                    "53010220051126133Y"};
    int i;

    for (i = 0; i < N; ++i)
        if (check_id(pid[i])) // 函数调用
            printf("%s\tTrue\n", pid[i]);
        else
            printf("%s\tFalse\n", pid[i]);

    return 0;
}
int check_id(char *str) {
    int i;
       if(strlen(str)!=18)
       return 0;
       else {
       
       for(i=0;i<=17;i++)
           if('0'<=str[i]<='9')
           break;
           else 
           return 0;}
       if(str[17]=='x'||'0'<=str[17]<='9')
       return 1;
}

 

 

实验七

代码:

#include <stdio.h>
#define N 80
void encoder(char *str, int n); // 函数声明
void decoder(char *str, int n); // 函数声明

int main() {
    char words[N];
    int n;

    printf("输入英文文本: ");
    gets(words);

    printf("输入n: ");
    scanf("%d", &n);

    printf("编码后的英文文本: ");
    encoder(words, n);      // 函数调用
    printf("%s\n", words);

    printf("对编码后的英文文本解码: ");
    decoder(words, n); // 函数调用
    printf("%s\n", words);

    return 0;
}


void encoder(char *str, int n) {
    int i=0;
    while(str[i]!='\0'){
        if((str[i]>='a'&&str[i]<='z')||(str[i]>='A'&&str[i]<='Z'))
        {
            if((str[i]>='a'&&str[i]+n<='z')||(str[i]>='A'&&str[i]+n<='Z')){
                str[i]+=n;
            }
            else{
                if(str[i]>='a')
                str[i]='a'+str[i]+n-'z'-1;
                else
                str[i]='A'+str[i]+n-'Z'-1;
            }    
        }
        i++;
    }
      
}


void decoder(char *str, int n) {
    int i=0;
    while(str[i]!='\0'){
        if((str[i]>='a'&&str[i]<='z')||(str[i]>='A'&&str[i]<='Z'))
        {
            if(str[i]>='a'&&str[i]+n<='z'){
                str[i]=((str[i]-'a'-n+26)%26)+'a';}
                else
                str[i]=((str[i]-'A'-n+26)%26)+'A';
            
        
        }
        i++;
    }
}

 

 

 

实验八

代码:

#include <stdio.h>
#include<string.h>
int main(int argc, char *argv[]) {
    int i,j;
    char *t;
    for(i=1;i<argc-1;i++){
        for(j=1;j<argc-1-i;j++){
            if(strcmp(argv[j],argv[j+1])>0){
                t=argv[j];
                argv[j]=argv[j+1];
                argv[j+1]=t;
            }
        }
    }
    
 
    for(i = 1; i < argc; ++i)
        printf("hello, %s\n", argv[i]);

    return 0;
}

 

posted @ 2024-12-08 19:58  夏庆兴  阅读(1)  评论(0编辑  收藏  举报