题目01：在一个已知的字符串中查找最长单词，假定字符串中只含字母和空格，空格用来分隔不同的单词。

直接编译，程序执行结果如下图所示：

题目02：编写一个int string_len(char *s)，返回字符串s的字符长度(不包括\0)。

直接编译，程序执行结果如下图所示：

C语言是一门通用计算机编程语言，应用广泛。C语言的设计目标是提供一种能以简易的方式编译、处理低级存储器、产生少量的机器码以及不需要任何运行环境支持便能运行的编程语言。

尽管C语言提供了许多低级处理的功能，但仍然保持着良好跨平台的特性，以一个标准规格写出的C语言程序可在许多电脑平台上进行编译，甚至包含一些嵌入式处理器（单片机或称MCU）以及超级电脑等作业平台。

#include <stdio.h>

#include <string.h>

struct Message

{

char name[10]

int number

char sort[4]

int price

char company[4]

struct Message *next

}

void Interface(void)

{

printf("\n*******************************\n")

printf(" 1：添加记录 2： 显示记录 \n")

printf(" 3：查询记录 4： 代号的排序 \n")

printf(" 5：删除记录 6： 保存记录 \n")

printf(" 7：退出 \n")

printf("*********************************\n")

return

}

struct Message * AddMessage(struct Message *head)

{

struct Message *message

message = (struct Message *) malloc (sizeof (struct Message))

printf("请输入名称: \n")

scanf("%s", message->name)

fflush(stdin)

printf("请输入代号: \n")

scanf("%d", &message->number)

fflush(stdin)

printf("请输入类别: \n")

scanf("%d", &message->sort)

fflush(stdin)

printf("请输入公司: \n")

scanf("%d", &message->company)

fflush(stdin)

printf("请输入价格: \n")

scanf("%d", &message->price)

message->next = NULL

if (head == NULL)

{

return message

}

else

{

message->next = head

return message

}

}

void ShowMessage(struct Message *head)

{

if (head == NULL)

{

printf("没有信息显示!\n")

}

else

{

while (head != NULL)

{

printf("股票名称: %s\n", head->name)

printf("代号: %d\n", head->number)

printf("类别: %s\n", head->sort)

printf("公司: %s\n", head->company)

printf("价格: %d\n", head->price)

head = head ->next

}

}

}

void SearchMessage(struct Message *head)

{

char name[10]

printf("请输入你要查询的名称: \n")

scanf("%s", name)

while (head != NULL)

{

if (strcmp(head->name, name) == 0)

{

printf("股票名称: %s\n", head->name)

printf("代号: %d\n", head->number)

printf("类别: %s\n", head->sort)

printf("公司: %s\n", head->company)

printf("价格: %d\n", head->price)

break

}

else

{

head = head->next

}

}

if (head == NULL)

{

printf("没有你要查询的信息\n")

}

}

void Sort(struct Message *head)

{

/* struct Message *temp

temp = (struct Message *)malloc(sizeof(struct Message))

memset(temp, 0, sizeof(struct Message))

struct Message *nextTo

nextTo = head->next

if (head != NULL &&nextTo != NULL)

{

while (head != NULL)

{

while (nextTo != NULL)

{

if (head->number >nextTo->number)

{

temp = head

head = nextTo

head ->next = temp

temp ->next = nextTo ->next

nextTo = temp

}

nextTo = nextTo->next

}

head = head->next

}

}

else

{

return

}

return*/

printf("暂时不能实现\n")

}

struct Message * RemoveMessage(struct Message *head)

{

struct Message *h = head

char name[10]

struct Message *nextTo, *p

printf("请输入你要删除的名称: \n")

scanf("%s", name)

if (head == NULL)

{

printf("还没有添加任何信息，无法删除!\n")

return head

}

else if (strcmp(head->name, name) == 0)

{

//p = head

head = head->next

return head

//free(p)

}

else

{

nextTo = head->next

while (strcmp(nextTo->name, name) != 0 &&nextTo != NULL)

{

head = nextTo

nextTo = nextTo ->next

}

if (strcmp(nextTo->name, name) == 0)

{

head->next = nextTo ->next

free(nextTo)

return h

}

else

{

printf("没有你要删除的信息!\n")

return h

}

}

return h

}

void SaveMessage(struct Message *head)

{

if (head == NULL)

{

return

}

FILE *fp

fp = fopen("file.txt", "ab+")

if (fp == NULL)

{

printf("打开文件出错!\n")

return

}

while (head != NULL)

{

fwrite(head, sizeof(struct Message), 1, fp)

head = head ->next

}

printf("保存成功!\n")

fclose(fp)

}

int main(void)

{

int choice

struct Message *head = NULL

while (1)

{

Interface()

printf("请选择功能项: \n")

scanf("%d", &choice)

switch (choice)

{

case 1:

head = AddMessage(head)

break

case 2:

ShowMessage(head)

break

case 3:

SearchMessage(head)

break

case 4:

Sort(head)

break

case 5:

head = RemoveMessage(head)

break

case 6:

SaveMessage(head)

break

case 7:

exit(1)

break

default:

printf("选择有误，请重新选项!\n")

}

}

return 0

}