数据结构算法C语言实现（十四）--- 4.1&4.2串的类型定义、表示及实现

　　一.简述

　　【暂无】

　　二.头文件

//4_2_part1.h
/**
author:zhaoyu
*/
//2016-6-10
//----串的定长顺序存储表示----
#include "head.h"
#define MAXSTRLEN 255//用户可以在255以内定义最大串长
//这语法还不是很熟悉
typedef unsigned char SString[MAXSTRLEN+1];//0 号单元存放串的长度
int StrLength(SString T)
{
    for (int i = 1; i <= MAXSTRLEN; ++i)
    {
        if ('\0' == T[i])
        {
            return i-1;
        }
    }
    return MAXSTRLEN;
}

/**
algorithm 4.2
*/
Status Concat(SString &T, SString S1, SString S2)
{
    //用 T 返回由 S1 和 S2 连接而成的新串。
    //若未截断，则返回 TRUE，否则返回 FALSE
    Status uncut;
    if (S1[0] + S2[0] < MAXSTRLEN)
    {//未截断
        int i = 1;
        for (i = 1; i <= S1[0]; ++i)
        {
            T[i] = S1[i];
        }
        for (i = 1; i <= S2[0]; ++i)
        {
            T[S1[0]+i] = S2[i];
        }
        T[0] = S1[0] + S2[0];
        uncut = TRUE;
    }
    else if (S1[0] < MAXSTRLEN)
    {
        int i = 1;
        for (i = 1; i <= S1[0]; i++)
        {
            T[i] = S1[i];
        }
        for (i = S1[0]+1; i <= MAXSTRLEN; i++)
        {
            T[i] = S2[i-S1[0]];
        }
        T[0] = MAXSTRLEN;
        uncut = FALSE;
    }
    else
    {
        for (int i = 1; i <= MAXSTRLEN; i++)
        {
            T[i] = S1[i];
        }
        T[0] = S1[0] = MAXSTRLEN;
        uncut = FALSE;
    }
    return uncut;
}
/**
algorithm 4.3
*/
Status SubString(SString &Sub, SString S, int pos, int len)
{
    //用 Sub 返回串 S 的第 pos 个字符起长度为 len 的字串
    //其中， 1<= pos <<= SreLength(S) 且 0 <= len <= StrLength(S)-pos+1
    if (pos < 1 || pos > S[0] || len < 0 || len > S[0]-pos+1)
    {
        return ERROR;
    }
    for (int i = 1; i <= len; i++)
    {
        Sub[i] = S[i+pos-1];
    }
    Sub[0] = len;
    return OK;
}
void PrintSString(SString T)
{
    //if(T[])
    for (int i = 1; i <= T[0]; ++i)
    {
        printf("%c", *(T+i));
    }
    printf("\n");
}

4_2_part1.h

//4_2_part2.h
/**
author:zhaoyu
*/
//2016-6-12
#include "head.h"
#include <cstdlib>
#include <cstring>
//----串的对分配存储表示----
typedef struct {
    char *ch;//
    int length;    
}HString;

Status StrInsert(HString &S, int pos, HString T)
{//1<= pos <= StrLength(S)+1
//在串的第 pos 个字符之前插入串 T
    if (1 < pos || pos > S.length + 1)
    {
        printf("Illegal pos\n");
        return ERROR;
    }
    if (T.length){//T 非空，则重新分配空间，插入 T
        if (!(S.ch = (char *)realloc(S.ch, (S.length +
         T.length)*sizeof(char))));
        {
            exit(OVERFLOW);
        }
        for (int i = S.length-1; i >= pos-1; i--)
        {//为插入 T 为腾出位置
            S.ch[i+T.length] = S.ch[i];
        }
        for (int i = pos-1; i <= pos+T.length-2; i++)
        {//插入 T
            S.ch[i] = T.ch[i];
        }
        S.length += T.length;    
    }
    return OK;
}
//page 76-77
//----基本操作的算法描述----
Status StrAssign(HString &T, char *chars)
{//生成一个其值等于串常量 chars的串 T
    if (T.ch)
    {
        T.ch = NULL;
    }
    int L;
    char *c;;
    for (L = 0, c = chars; *c!='\0'; ++L, ++c);//求 chars 的长度 L
    if(!L)
    {
        T.ch = NULL;
        T.length = 0;
    }
    else
    {
        if (!(T.ch = (char *)malloc(L*sizeof(char))))
        {
            exit(OVERFLOW);
        }
        for (int i = 0; i < L; ++i)
        {
            T.ch[i] = chars[i];
        }
        T.length = L;
    }
    return OK;
}
int StrLength(HString S)
{//返回 S 的元素个数， 称为串的长度
    return S.length;
}
int StrCompare(HString S, HString T)
{//若 S >|=|< T，则返回 >|=|< 0
    for (int i = 0; i < S.length && i < T.length; i++)
    {
        if (T.ch[i] != S.ch[i])
        {
            return S.ch[i] - T.ch[i];
        }
    }
    return S.length - T.length;
}
Status ClearString(HString &S)
{
    //将 S 清空为空串
    if (S.ch)
    {
        free(S.ch);
        S.ch = NULL;
    }
    S.length = 0;
    return OK;
}
Status Concat(HString &T, HString S1, HString S2)
{
    if (T.ch)
    {//释放旧空间
        free(T.ch);
    }
    if (!(T.ch = (char *)malloc((S1.length+S2.length)*sizeof(char))))
    {
        exit(OVERFLOW);
    }
    for (int i = 0; i < S1.length; ++i)
    {
        T.ch[i] = S1.ch[i];
    }
    for (int i = 0; i < S2.length; ++i)
    {
        T.ch[i+S1.length] = S2.ch[i];
    }
    T.length = S1.length + S2.length;
    return OK;
}
Status SubString(HString &Sub, HString S, int pos, int len)
{
    //用 Sub 返回串 S 的第 pos 个字符起长度为 len 的子串
    //其中，其中， 1<= pos <<= SreLength(S) 且 0 <= len <= StrLength(S)-pos+1
    if (pos < 1 || pos > S.length || len < 0 || len > S.length-pos+1)
    {
        return ERROR;
    }
    if (Sub.ch)
    {
        free(Sub.ch);
    }
    if (!len)
    {//空子串
        Sub.ch = NULL;
        Sub.length = 0;
    }
    else
    {
        Sub.ch = (char *)malloc(len*sizeof(char));
        for (int i = 0; i < len; ++i)
        {
            Sub.ch[i] = S.ch[pos+i-1];
        }
        Sub.length = len;
    }
    return OK;
}
void PrintHString(HString S)
{
    for (int i = 0; i < S.length; ++i)
    {
        printf("%c", S.ch[i]);
    }
    printf("\n");
}

　　三.CPP文件

#include "4_2_part1.h"
int main(int argc, char const *argv[])
{
    SString S1;
    SString S2;
    SString T;
    scanf("%s", S1+1);
    *S1 = StrLength(S1);
    scanf("%s", S2+1);
    *S2 = StrLength(S2);
    Concat(T, S1, S2);
    PrintSString(T);
    int pos = 2, len = 5;
    SubString(T, S1, pos, len);
    PrintSString(T); 
    return 0;
}

#include "4_2_part2.h"
int main(int argc, char const *argv[])
{
    char S[100];
    HString T = {NULL, 0};
    HString S1 = {NULL, 0};
    HString S2 = {NULL, 0};
    scanf("%s", S);
    StrAssign(S1, S);
    printf("S1:\t");
    PrintHString(S1);
    printf("StrLength\t%d\n", StrLength(S1));
    scanf("%s", S);
    StrAssign(S2, S);
    printf("S2\t");
    PrintHString(S2);
    printf("StrLength\t%d\n", StrLength(S1));
    printf("Compare S1 vs S2\t%d\n", StrCompare(S1, S2));
    Concat(T, S1, S2);
    printf("T = S1 + S2\t");
    PrintHString(T);
    SubString(S1, T, 2, 3);
    printf("Sub :T[2]-T[4]\t");
    PrintHString(S1);
    return 0;
}

　　四.测试

　　连接

　　

　　求子串

　　

　　比较串