通过实例测试串的基本操作，如 串的赋值、串的插入、串的删除、串的替换、串的销毁。

头文件：函数的声明

#include <stdio.h>#include <stdlib.h>#include <string.h>typedef struct{char *str;int length;}HeapString;void InitString(HeapString *S);//串的初始化操作void StrAssign(HeapString *S,char cstr[]);//串的赋值操作int StrEmpty(HeapString S);//判断串是否为空int StrLength(HeapString S);//求串的长度操作void StrCopy(HeapString *T,HeapString S);//串的复制操作int StrCompare(HeapString S,HeapString T);//串的比较操作int StrInsert(HeapString *S,int pos,HeapString T);//串的插入操作int StrDelete(HeapString *S,int pos,int len);//串的删除操作int StrConcat(HeapString *T,HeapString S);//串的连接操作int SubString(HeapString *Sub,HeapString S,int poos,int len);//截取子串操作int StrReplace(HeapString *S,HeapString T,HeapString V);//串的替换操作int StrIndex(HeapString S,int pos,HeapString T);//串的定位操作void StrClear(HeapString *S);//清空串操作void StrDestory(HeapString *S);//摧毁串操作void StrPrint(HeapString S);//串的输出声明

函数的定义

#include "串.h"void InitString(HeapString *S){S->length = 0;S->str = '\0';}void StrAssign(HeapString *S,char cstr[])//串的赋值操作(将常量cstr中的字符赋值给串S){int i = 0,len;if(S->str){free(S->str);}for(i = 0;cstr[i]!='\0';i++){;}len = i;if(!i){S->length = 0;S->str = '\0';}else{S->str = (char*)malloc(len*sizeof(char));if(!S->str){exit(-1);}for(i = 0;i < len;i++){S->str[i] = cstr[i];}S->length = len;}}int StrEmpty(HeapString S)//判断串是否为空{if(S.length == 0){return 1;}else{return 0;}}int StrLength(HeapString S)//求串的长度操作{return S.length ;}void StrCopy(HeapString *T,HeapString S)//串的复制操作(将串S中的每一个字符赋给T){int i;T->str = (char*)malloc(S.length*sizeof(char));if(!T->str){exit(-1);}for(i = 0;i < S.length ;i++){T->str[i] = S.str[i];}T->length = S.length ;}int StrCompare(HeapString S,HeapString T)//串的比较操作{int i;for(i = 0;i < S.length&&i < T.length ;i++)//比较两个串中的字符{if(S.str[i] != T.str[i])//如果出现字符不同，则返回两个字符的差值{return (S.str[i]-T.str[i]);}}return (S.length - T.length);//如果比较完毕，返回两个字符串的长度的差值}int StrInsert(HeapString *S,int pos,HeapString T)//串的插入操作(在串S的pos个位置插入串T){int i;if(pos < 0 || pos-1 > S->length){printf("插入位置不正确\n");return 0;}S->str = (char*)realloc(S->str,(S->length+T.length)*sizeof(char));if(!S->str){printf("内存分配失败");exit(-1);}for(i = S->length -1;i >= pos-1;i--){S->str[i+T.length] = S->str[i];}for(i = 0;i < T.length ;i++){S->str[i+pos-1] = T.str[i];}S->length = S->length + T.length;return 1;}int StrDelete(HeapString *S,int pos,int len)//串的删除操作(在串S中删除pos开始的len个字符,然后将后面的字符向前移动){int i;char *p;if(pos < 0 || len < 0 || pos+len-1 > S->length){printf("删除位置不正确，参数len不合法\n");return 0;}p = (char*)malloc(S->length-len);if(!p){exit(-1);}for(i = 0;i < pos-1;i++)//将串第pos位置之前的字符复制到p中{p[i] = S->str[i];}for(i = pos-1;i < S->length-len;i++)//将串第pos+len位置以后的字符复制到p中{p[i] = S->str[i+len];}S->length = S->length -len;//修改串的长度free(S->str);//释放原来的串S的内存空间S->str = p;//将串的str指向p字符串return 1;}int StrConcat(HeapString *T,HeapString S)//串的连接操作(将串S连接在串T的后面){int i;T->str = (char*)realloc(T->str ,(T->length +S.length )*sizeof(char));if(!T->str){printf("分配空间失败");exit(-1);}else{for(i = T->length ;i < T->length +S.length ;i++)//将串S直接连接到T的末尾{T->str[i] = S.str[i-T->length];}T->length = T->length +S.length ;//修改串T的长度}return 1;}int SubString(HeapString *Sub,HeapString S,int pos,int len)//截取子串操作(截取串S中从第pos个字符开始，长度为len的连续字符，并赋值给Sub){int i;if(Sub->str){free(Sub->str);}if(pos < 0 || len < 0 || pos+len-1 > S.length){printf("参数pos和len不合法\n");return 0;}else{Sub->str = (char*)malloc(len*sizeof(char));if(!Sub->str){printf("存储分配失败");exit(-1);}for(i = 0;i < len;i++){Sub->str[i] = S.str[i+pos-1];}Sub->length = len;return 1;}}int StrIndex(HeapString S,int pos,HeapString T)//串的定位操作(在主串S中的第pos个位置开始查找子串T,如果主串S中存在与串T值相等的子串，返回子串在主串第pos个字符后第一次出现的位置){int i,j;if(StrEmpty(T)){return 0;}i = pos;j = 0;while(i < S.length && j < T.length){if(S.str[i] == T.str[j]){i++;j++;}else//如果当前对应位置的字符不相等，则从串S的下一个字符开始，从T的第0个字符开始比较{i = i-j+1;j = 0;}}if(j >= T.length)//如果在串S中找到串T，则返回子串T在主串S中的位置{return i-j+1;}else{return -1;}}int StrReplace(HeapString *S,HeapString T,HeapString V)//串的替换操作(如果串S中存在子串T，则用V替换串S中的所有子串T){int flag;int i = 0;if(StrEmpty(T)){return 0;}do{i = StrIndex(*S,i,T);//利用串的定位操作在串S中查找T的位置if(i){StrDelete(S,i,StrLength(T));//如果找到子串T,则将S中的串T删除flag = StrInsert(S,i,V);//将V插入if(!flag){return 0;}i += StrLength(V);}}while(i);return 1;}void StrClear(HeapString *S)//清空串操作{if(S->str){free(S->str);}S->str = '\0';S->length = 0;}void StrDestory(HeapString *S)//摧毁串操作{if(S->str){free(S->str);}}void StrPrint(HeapString S)//串的输出声明{int i;for(i = 0;i < S.length ;i++){printf("%c",S.str[i]);}printf("\n");}

函数的应用

#include "串.h"/*例如串S1=“Welcome to”,S2="China",Sub="Xi'an",将串S2连接到串S1末尾，然后将串S1中的S2用Sub替换*/int main(void){HeapString S1,S2,Sub;char ch[50];InitString(&S1);InitString(&S2);InitString(&Sub);printf("请输入第一个字符串：");gets(ch);StrAssign(&S1,ch);printf("经过赋值操作后的串S1：\n");StrPrint(S1);printf("请输入第二个字符串：");gets(ch);StrAssign(&S2,ch);printf("经过赋值操作后的串S2：\n");StrPrint(S2);printf("将串S2连接到串S1的末尾，S1串为：\n");StrConcat(&S1,S2);StrPrint(S1);printf("经过赋值操作后的串Sub：\n");StrAssign(&Sub,"Everyone");StrPrint(Sub);printf("将串S2插入到串S1的第一个位置：\n");StrInsert(&S1,1,Sub);StrPrint(S1);printf("把串S1的第一个位置之后的八个字符删除：\n");StrDelete(&S1,1,8);StrPrint(S1);printf("将串S1中的S2置换成Sub：\n");StrAssign(&Sub,"Xi'an");StrReplace(&S1,S2,Sub);StrPrint(S1);StrDestory(&S1);StrDestory(&S2);StrDestory(&Sub);return 0;}