数据结构C语言动态分配实现串

说明：堆分配存储实现串时，串并不是以’\0‘， 而是用数据项int length来表示的，所以和传统的c语言操作字符串有所不同。

头文件

#ifndef PILEHEAD_H_INCLUDED

#define PILEHEAD_H_INCLUDED

#include <stdio.h>

#include <stdlib.h>

typedef struct

{

char* ch ;

int len ;

}HString ;

int StrAssign( HString* pstr , char* pch ) ;

int StrLength( HString* pstr ) ;

int StrCompaer( HString* pstr1 , HString* pstr2 ) ;

int StrClear( HString* pstr ) ;

int StrConcat( HString* pstr , HString str1 , HString str2 ) ;

int StrSub( HString* sub , HString pstr , int pos , int length ) ;

int StrPrint( HString* pstr ) ;

#endif // PILEHEAD_H_INCLUDED

函数实现

#include "pilehead.h"

int StrAssign( HString* pstr , char* pch )

{

if( !pstr->len )

{

free( pstr->ch ) ;

}

int i ;

for( i = 0 ; pch[i] != '\0' ; i++ )

{

;

}

if( i == 0 )

{

pstr->ch = NULL ;

pstr->len = 0 ;

}

else

{

pstr->ch = ( char* )malloc( i * sizeof( char ) ) ;

pstr->len = i ;

}

i = 0 ;

while( i < pstr->len )

{

pstr->ch[i] = pch[i] ;

i++ ;

}

return 0 ;

}

int StrPrint( HString* pstr )

{

int i = 0 ;

while( i < pstr->len )

{

printf( "%c" , pstr->ch[i] ) ;

i++ ;

}

printf( "\n" ) ;

return 0 ;

}

int StrLength( HString* pstr )

{

return pstr->len ;

}

int StrCompaer( HString* pstr1 , HString* pstr2 )

{

int i = 0 ;

int ret = 0 ;

while( i < pstr1->len && i <pstr2->len )

{

ret = pstr1->ch[i] - pstr2->ch[i] ;

if( ret < 0 )

{

return -1 ;

}

else if( ret > 0 )

{

return 1 ;

}

else

{

i++ ;

}

}

int diff = pstr1->len - pstr2->len ;

if( diff < 0 )

{

return -1 ;

}

else if( diff == 0 )

{

return 0 ;

}

return 1 ;

}

int StrClear( HString* pstr )

{

if( pstr->ch )

{

free( pstr->ch ) ;

pstr->ch = NULL ;

}

pstr->len = 0 ;

return 0 ;

}

int StrConcat( HString* pstr , HString str1 , HString str2 )

{

StrClear( pstr ) ;

StrAssign( pstr , str1.ch ) ;

int len = str1.len ;

int len2 = 0 ;

while( len2 < str2.len )

{

pstr->ch[len++] = str2.ch[len2++] ;

}

pstr->len = str1.len + str2.len ;

return 0 ;

}

int StrSub( HString* sub , HString pstr , int pos , int length )

{

if( pos < 1 || pos > pstr.len || length < 1 || length > pstr.len - pos + 1 )

{

printf( "ERROR!\n" ) ;

exit( 1 ) ;

}

StrClear( sub ) ;

sub->ch = ( char* )malloc( length * sizeof( char ) ) ;

sub->len = length ;

int i = 0 ;

while( i < length )

{

sub->ch[i] = pstr.ch[pos - 1 + i] ;

i++ ;

}

return 0 ;

}

测试函数

#include "pilehead.h"

int main()

{

HString str ;

HString str1 ;

HString str2 ;

char* pch = "abcd" ;

StrAssign( &str , pch ) ;

StrAssign( &str1 , "abcd" ) ;

StrAssign( &str2 , "fhasdifhos" ) ;

StrPrint( &str ) ;

StrPrint( &str1 ) ;

/*StrClear( &str ) ;

StrPrint( &str ) ;

int i = StrCompaer( &str , &str1 ) ;

printf( "%d" , i ) ;*/

StrConcat( &str , str1 , str2 ) ;

StrPrint( &str ) ;

HString s ;

StrSub( &s ,str , 4 , 5 ) ;

StrPrint( &s ) ;

return 0;

}