C语言数据结构之动态分配实现串

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 ) ; StrConcat( &str , str1 , str2 ) ; StrPrint( &str ) ; HString s ; StrSub( &s ,str , 4 , 5 ) ; StrPrint( &s ) ; return 0;}

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