1.1串

引子——

​ 字符串简称为串，串是由字符元素构成的，其中元素的逻辑关系也是一种线性关系。串的处理在计算机非数值处理中占用重要的地位，如信息检索系统，文字编辑等都是以串数据作为处理对象

串是由零个或多个字符组成的有限序列。

两个串相等，当且仅当两个串长度相等且对应位置上字符一样

1.2串的抽象数据类型

（如图所示）

---

1.3顺序串基本算法实现

和线性表一样，串也要顺序存储结构和链式存储结构，前者称为顺序串，后者称为链串

顺序串的存储方式又有两种。一种是每个字只存一个字符，这称为非紧缩格式。另一种是每个字存放多个字符，称为紧凑格式。

（1）声明

typedef struct
{char data[MaxSize]; int length;
}SqString; //存放串字符//存放串长//顺序串类型

(2)生成串

void StrAssign(SqString& s, char cstr[]) {int i;for (i = 0; cstr[i] != '\0'; i++)s.data[i] = cstr[i];s.length = i; //s为引用型参数//设置串s的长度
}

(3)销毁串

void DestroyStr(SqString&s)
{ }

(4)串的复制

void StrCopy(SqString& s, SqString t)
{//s为引用型参数int i;for (i = 0; i < t.length; i++)s.data[i] = t.data[i];s.length = t.length;//复制t的所有字符//设置串s的长度
}

(5)判断串相等

//判断串相等
bool StrEqual(SqString s,SqString t) {bool same=true; int i; if(s.length!=t.length)same=false; else for (i=0;i<s.length;i++) if (s.data[i] = t.data[i]){same = false;break;}return same;
}

(6)求串长

int StrLength(SqString s)
{return s.length;
}

(7)串的连接

SqString Concat(SqString s, SqString t)
{SqString str;int i;str.length = s.length + t.length;for (i = 0; i < s.length; i++)str.data[i] = s.data[i];for (int i = 0; i < t.length; i++)str.data[s.length + i] = t.data[i];return str;
}

(8)字串插入

SqString InsStr(SqString s1, int i, SqString s2)
{int j;SqString str;	//定义结果串str.length = 0;if (i <= 0 || i > s1.length + 1)return str;for (j = 0; j < i - 1; j++)str.data[j] = s1.data[j];for (j = 0; j < s2.length; j++)str.data[i + j - 1] = s2.data[j];for (j = i - 1; j < s1.length; j++)str.data[s2.length + j] = s1.data[j];str.length = s1.length + s2.length;return str;
}

(9)字串删除

SqString DelStr(SqString s, int i, int j)
{int k;SqString str;str.length = 0;if (i <= 0 || i > s.length || i + j > s.length + 1)return str;for (k = 0; k < i - 1; k++)str.data[k] = s.data[k];for (k = i + j - 1; k < s.length; k++)str.data[k - j] = s.data[k];str.length = s.length - j;return str;
}

(10)字串替换

//字串的替换
SqString RepStr(SqString s, int i, int j, SqString t)
{int k;SqString str;str.length = 0;if (i <= 0 || i > s.length || i + j > s.length + 1)return str;for (k = 0; k < i - 1; k++)str.data[k] = s.data[k];for (k = 0; k < t.length; k++)str.data[i + k - 1] = t.data[k];for (k = i + j - 1; k < s.length; k++)str.data[t.length + k - j] = s.data[k];str.length = s.length - j + t.length; return str;
}

(11)输出串

//输出串
void DispStr(SqString s)
{int i;if (s.length > 0){for (i = 0; i < s.length; i++)printf("%c", s.data[i]);printf("\n");}
}

1.4链串

串的链式存储结构是链串，这里介绍采用带头结点的单链表作为链串。

（如图）

---

1.5链串的基本算法实现

（1）声明

typedef struct snode {char data;struct snode* next;
}LinkStrNode;

(2)尾插法生成串

//尾插法建立链串
void StrAssign(LinkStrNode*& s, char cstr[])
{int i;LinkStrNode* r, * p;s = (LinkStrNode*)malloc(sizeof(LinkStrNode));r = s;for (i = 0; cstr[i] != '\0'; i++){p = (LinkStrNode*)malloc(sizeof(LinkStrNode));p->data = cstr[i];r->next = p;r = p;}r->next = NULL;
}

（3）销毁串

//销毁串
void DestroyStr(LinkStrNode*&s)
{LinkStrNode* pre = s, * p = s->next;while (p != NULL){free(pre);pre = p;p = pre->next;}
}

(4)串的复制

void StrCopy(LinkStrNode*& s, LinkStrNode* t)
{LinkStrNode* p = t->next, * q, * r;s = (LinkStrNode*)malloc(sizeof(LinkStrNode));r = s;while (p != NULL){q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p->data;r->next = q; r = q;p = p->next;}r->next = NULL;
}

(5)判断串相等

//判断串相等
bool StrEqual(LinkStrNode* s, LinkStrNode* t)
{LinkStrNode* p = s->next, * q = t->next;while (p != NULL && q != NULL && p->data == q->data){p = p->next;q = q->next;}if (p == NULL && q == NULL)return true;return false;
}

(6)求串长

//求串长
int StrLength(LinkStrNode* s)
{int  i = 0;LinkStrNode* p = s->next;while (p != NULL){i++;p = p->next;}return i;
}

(7)串的连接

LinkStrNode* contact(LinkStrNode * s, LinkStrNode * t)
{LinkStrNode* str, * p = s->next, * q, * r;str = (LinkStrNode*)malloc(sizeof(LinkStrNode));r = str;while (p != NULL){q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p->data;r->next = q;r = p;p = p->next;}p = t->next;while (p != NULL){q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p->data;r->next = q; r = q;p = p->next;}r->next = NULL;return  str;
}

(8)求子串

//求子串
LinkStrNode* SubStr(LinkStrNode* s, int i, int j)
{int k;LinkStrNode* str, * p = s->next, * q, * r;str = (LinkStrNode*)malloc(sizeof(LinkStrNode));str->next = NULL;if (i <= 0 || i > StrLength(s) || j<0 || i + j - 1>StrLength(s))return str;for (k = 1; k < i; k++)p = p->next;for (k = 1; k <= j; k++){q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p->data;r->next = q;r = q;p = p->next;}r->next = NULL;return NULL;
}

(9)子串插入

//子串插入
LinkStrNode* InsStr(LinkStrNode* s, int i, LinkStrNode* t)
{int k;LinkStrNode* str, * p = s->next, * pl = t->next, * q, * r;str = (LinkStrNode*)malloc(sizeof(LinkStrNode));str->next = NULL;r = str;if (i <= 0 || i > StrLength(s) + 1)return str;for (k = 1; k < i; k++) //置结果串str为空串//:指向结果串的尾结点//参数不正确时返回空申//将s的前i个结点复制到str {q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p->data;r->next = q; r = q;p = p->next;}while (pl!=NULL) { //将t的所有结点复制到str q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = pl->data;r->next = q; r = q;pl = pl->next;}while (p != NULL) {//将t的所有结点复制到str q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p->data;r->next = q; r = q;p = p->next;}r->next = NULL;
}

(10)子串删除

//字串删除
LinkStrNode* DelStr(LinkStrNode* s, int i, int j)
{int k;LinkStrNode* str, * p = s->next,*q, * r;str = (LinkStrNode*)malloc(sizeof(LinkStrNode));str->next = NULL;r = str;if (i <= 0 || i > StrLength(s) || j<0 || i + j - 1>StrLength(s));return str;for (int k = 1; k < i; k++){q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p->data;r->next = q; r = q;p = p->next;}for (k = 0; k < j; k++)p = p->next;while (p != NULL){q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p->data;r->next = q;r = q;p = p->next;}r->next = NULL;return str;
}

(11)子串的替换

//子串的替换
LinkStrNode* RepStr (LinkStrNode* s, int i, int j, LinkStrNode* t)
{int k;LinkStrNode* str, * p = s->next, * p1 = t->next, * q, * r;str = (LinkStrNode*)malloc(sizeof(LinkStrNode));str->next = NULL;r = str;if (i <= 0 || i > StrLength(s) || j<0 || i + j - 1>StrLength(s))return str;for (int k = 0; k < i - 1; k++){q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p->data; q->next = NULL;r->next = q; r = q;p = p->next;}for (k = 0; k < j; k++)p = p->next;while(p1 !=NULL){q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p1->data; aa222q->next = NULL;r->next = q; r = q;p1 = p1->next;}while (p != NULL){q = (LinkStrNode*)malloc(sizeof(LinkStrNode));q->data = p->data; q->next = NULL;r->next = q; r = q;p = p->next;}r->next = NULL;return str;
}

(12)输出串

输出串
void DispStr(LinkStrNode* s)
{LinkStrNode* p = s->next;while (p != NULL){printf("%c", p->data);p = p->next;}printf("\n");
}

希望本文对你有所帮助！