串的定长表示

思想和代码都不难，和线性表也差不多，串本来就是数据受限的线性表。

串连接：

      #include <stdio.h>
      #include <string.h>
      //串的定长顺序存储表示
      #define MAXSTRLEN 255 //用户可在255以内定义最大串长
      typedef unsigned char SString[MAXSTRLEN + 1];	//0号单元存放串的长度
      int Concat(SString *T,SString S1,SString S2)
     	//用T返回S1和S2联接而成的新串。若未截断返回1，若截断返回0
      {
     	int i = 1,j,uncut = 0;
     	if(S1[0] + S2[0] <= MAXSTRLEN)	//未截断
      	{
     		for (i = 1; i <= S1[0]; i++)//赋值时等号不可丢
      			(*T)[i] = S1[i];
     		for (j = 1; j <= S2[0]; j++)
      			(*T)[S1[0]+j] = S2[j];	//(*T)[i+j] = S2[j]
      		(*T)[0] = S1[0] + S2[0];
      		uncut = 1;
      	}
     	else if(S1[0] < MAXSTRLEN)		//截断
      	{
     		for (i = 1; i <= S1[0]; i++)//赋值时等号不可丢
      			(*T)[i] = S1[i];
     		for (j = S1[0] + 1; j <= MAXSTRLEN; j++)
      		{
      			(*T)[j] = S2[j - S1[0] ];
      			(*T)[0] = MAXSTRLEN;
      			uncut = 0;
      		}
      	}
     	else
      	{
     		for (i = 0; i <= MAXSTRLEN; i++)
      			(*T)[i] = S1[i];
     		/*或者分开赋值，先赋值内容，再赋值长度
       for (i = 1; i <= MAXSTRLEN; i++)
       (*T)[i] = S1[i];
       (*T)[0] = MAXSTRLEN;
       */
      		uncut = 0;
      	}
     	return uncut;
      }
      int 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的子串
     	//其中，1 ≤ pos ≤ StrLength(S)且0 ≤ len ≤ StrLength(S) - pos + 1(从pos开始到最后有多少字符)
     	//第1个字符的下标为1,因为第0个字符存放字符长度
      {
     	int i;
     	if(pos < 1 || pos > S[0] || len < 0 || len > S[0] - pos + 1)
     		return 0;
     	for (i = 1; i <= len; i++)
      	{
     		//S中的[pos,len]的元素 -> *Sub中的[1,len]
      		(*Sub)[i] = S[pos + i - 1];//下标运算符 > 寻址运算符的优先级
      	}
      	(*Sub)[0] = len;
     	return 1;
      }
      void PrintStr(SString S)
      {
     	int i;
     	for (i = 1; i <= S[0]; i++)
     		printf("%c",S[i]);
     	printf("\n");
      }
      int main(void)
      {
     	/*定长顺序存储初始化和打印的方法
       SString s = {4,'a','b','c','d'};
       int i;
       //s = "abc"; //不可直接赋值
       for (i = 1; i <= s[0]; i++)
       printf("%c",s[i]);
       */
      	SString s1 = {4,'a','b','c','d'};
      	SString s2 = {4,'e','f','g','h'},s3;
      	SString T,Sub;
     	int i;
     	for (i = 1; i <= 255; i++)
      	{
      		s3[i] = 'a';
     		if(i >= 248)
      			s3[i] = 'K';
      	}
      	s3[0] = 255;
      	SubString(&Sub,s3,247,8);
      	PrintStr(Sub);
     	return 0;
      }
  
 

文章来源: fantianzuo.blog.csdn.net，作者：兔老大RabbitMQ，版权归原作者所有，如需转载，请联系作者。

原文链接：fantianzuo.blog.csdn.net/article/details/83505987