C语言数据结构之模式匹配字符串定位问题

主要实现了三种字符串的模式匹配，主要包括字符串子操作的集合，字符串指针回溯，和KMP算法

头文件

#ifndef INDEXHEAD_H_INCLUDED#define INDEXHEAD_H_INCLUDED#include <stdio.h>#include <stdlib.h>#include <string.h>#define MAXLEN 255typedef char Sstring[MAXLEN + 1] ;int StrAssign( Sstring str , char* ps ) ;int StrLength( Sstring str ) ;int StrPrint( Sstring str ) ;int StrCompare( Sstring str1 , Sstring str2 ) ;int StrSub( Sstring sub , Sstring str , int pos , int length ) ;int StrIndex1( Sstring str , Sstring sub , int pos ) ;int StrIndex2( Sstring str , Sstring sub , int pos ) ;int StrIndex3( Sstring str , Sstring sub , int pos ) ;int GetNext( Sstring str , int next[] ) ;#endif // INDEXHEAD_H_INCLUDED

函数实现

#include "indexhead.h"int StrAssign( Sstring str , char* ps ){ int i = 0 ; if( strlen( ps ) > MAXLEN ) { printf( "ERROR!\n" ) ; exit( 1 ) ; } str[i++] = strlen( ps ) ; while( i <= strlen( ps ) ) { str[i] = *( ps + i - 1 ) ; i++ ; } return 0 ;}int StrPrint( Sstring str ){ int i = 1 ; while( i <= str[0] ) { printf( "%c" , str[i++] ) ; } printf( "\n" ) ; return 0 ;}int StrLength( Sstring str ){ return str[0] ;}int StrCompare( Sstring str1 , Sstring str2 ){ int i = 1 ; int ret = 0 ; while( i <= str1[0] && i <= str2[0] ) { ret = ( unsigned char )str1[i] - ( unsigned char )str2[i] ; if( ret < 0 ) { return -1 ; } else if( ret > 0 ) { return 1 ; } else { i++ ; } } if( i <= str1[0] ) { return -1 ; } else if( i <= str2[0] ) { return 1 ; } else { return 0 ; }}int StrSub( Sstring sub , Sstring str , int pos , int length ){ if( pos < 1 || pos > str[0] || length < 0 || length > str[0] - pos + 1 ) { printf( "ERROR!\n" ) ; exit( 1 ) ; } int i = 1 ; sub[0] = length ; while( i <= length ) { sub[i] = str[pos + i - 1] ; i++ ; } return 0 ;}int StrIndex1( Sstring str , Sstring sub , int pos ){ pos = 1 ; Sstring stemp ; while( pos <= str[0] - sub[0] + 1 ) { StrSub( stemp , str , pos , sub[0] ) ; if( !StrCompare( stemp , sub ) ) { return pos ; } pos++ ; } return 0 ;}int StrIndex2( Sstring str , Sstring sub , int pos ){ if( pos < 1 || pos > str[0] - sub[0] + 1 ) { printf( "ERROR!\n" ) ; exit( 1 ) ; } int i = pos ; int j = 1 ; while( ( i <= str[0] - sub[0] + 1 ) && ( j <= sub[0] ) ) { if( str[i] == sub[j] ) { i++ ; j++ ; } else { i = i - j + 2 ; j = 1 ; } } if( j > sub[0] ) { return i - sub[0] ; } return 0 ;}int GetNext( Sstring str , int next[] ){ int i = 1 ; next[1] = 0 ; int j = 0 ; while( i < str[0] ) { if( j== 0 || str[i] == str[j] ) { ++i ; ++j ; next[i] = j ; } else { j = next[j] ; } } return 0 ;}int StrIndex3( Sstring str , Sstring sub , int pos ){ int i = pos ; int j = 1 ; int next[ sub[0] ] ; GetNext( sub , next ) ; while( i <= str[0] && j <= sub[0] ) { if( j == 0 || str[i] == sub[j] ) { ++i ; ++j ; } else { j = next[j] ; } } if( j > sub[0] ) { return i - sub[0] ; } return 0 ;}

测试匹配函数

#include "indexhead.h"int main(){ /*Sstring str ; Sstring str1 ; char* p = "hello" ; StrAssign( str , p ) ; StrAssign( str1 , "ahello" ) ; StrPrint( str ) ; int i = StrLength( str ) ; printf( "%d\n" , i ) ; int j = StrCompare( str , str1 ) ; printf( "%d\n" , j ) ; StrSub( str , str1 , 3 , 4 ) ; StrPrint( str ) ;*/ Sstring str1 ;//验证StrIndex3() Sstring sub ; StrAssign( str1 , "shfiodshfdghafhs" ) ; StrAssign( sub , "dgh" ) ; int i = StrIndex3( str1 , sub , 1 ) ; printf( "%d\n" , i ) ; return 0;}

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