串的定长表示

旧城等待， 2022-05-15 13:50 25阅读 0赞

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。

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串连接：

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#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;
    }

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