Dynamic allocation of implementation strings for C language data structures
- 2020-06-01 10:26:35
- OfStack
Dynamic allocation of implementation strings for C language data structures
Note: when the heap allocates the storage implementation string, the string is not represented by '\0 ', but by the data item int length, so it is different from the traditional c language operation string.
The header file
#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
function
#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 ;
}
Test functions
#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;
}
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