C语言编程；基于有限状态机程序的字符模式识别
我正在用C语言构建一个模式识别程序，它可以读取用户定义的字符串和用户定义的4个字符的模式。然后，该程序有一个函数来确定是否找到了模式以及模式（根据输入文本索引）最初是在哪里找到的 我知道这对你们大多数人来说都是基本的，我只是希望能很快成为一名更熟练的程序员。当我执行我的程序时，它以一种我不理解的方式陷入无限循环 我知道问题在于FindMatch函数，而不是输入文本和模式的读入。我的FindMatch函数有什么问题？！请帮忙C语言编程；基于有限状态机程序的字符模式识别,c,pointers,state-machine,C,Pointers,State Machine,我正在用C语言构建一个模式识别程序，它可以读取用户定义的字符串和用户定义的4个字符的模式。然后，该程序有一个函数来确定是否找到了模式以及模式（根据输入文本索引）最初是在哪里找到的 我知道这对你们大多数人来说都是基本的，我只是希望能很快成为一名更熟练的程序员。当我执行我的程序时，它以一种我不理解的方式陷入无限循环 我知道问题在于FindMatch函数，而不是输入文本和模式的读入。我的FindMatch函数有什么问题？！请帮忙 #include <stdio.h> #include &l
#include <stdio.h>
#include <stdlib.h>
char *getCharBlock(int *size);
int findmatchA(char *text, char *pattern, int tsize, int psize);
void printIt(char *ptr, int index, int size);
int main(){
char *text, *pattern; //pointers for the characters you will read
char *p,*q,*r; //some pointer variables
int tsize,psize,x,y,z; //some integers
printf("Please input a sequence of character text (characters only will be stored):");
text = getCharBlock(&tsize);
printf(" Now input the pattern you seek to search for: ");
pattern = getCharBlock(&psize);
x = findmatch(text,pattern,tsize, psize);
if(x== -1){
printf("No Match Found \n");
printf("No starting position for match exists \n");
}
else{
printf("Match Has Been Found! \n");
printf("Match starting position at index %d \n", x);
printf("Remaining text after Match: \n");
printIt(text, x+psize, tsize);
}
free(text);
free(pattern);
}
char *getCharBlock(int *size){
char *input = (char*) malloc (80*sizeof(char));
char a;
int i = 0;
a = getchar();
while(i<80 && a!= '\n'){
if( (a>= 'a' && a <= 'z') || (a>= 'A' && a <= 'Z') ){
*(input + i) = a;
i++;
}
a = getchar();
}
*size = i;
return input;
}
int findmatch(char *text, char *pattern, int tsize, int psize) {
int index = 0;
int state = 0;
while (psize <= tsize) {
if ((*(text + index) == *pattern) && state == 0){
state = 1;
index++;
printf( "test 1 \n");
}
else if ((*(text + index) != *pattern) && state == 0){
state = 0;
index++;
printf( "test1.1 \n");
}
else if (*(text + index) == *(pattern + 1) && state ==1) {
state = 2;
index++;
printf( "test 2 \n");
}
else if (*(text + index) != *(pattern + 1) && state ==1) {
state = 0;
printf("test 2.2 \n");
}
else if (*(text + index) == *(pattern + 2) && state ==2) {
state = 3;
printf("test 3 \n");
}
else if (*(text + index) != *(pattern + 2) && state ==2) {
state = 0;
printf("test 3.3 \n");
}
else if (*(text + index) == *(pattern + 3) && state ==3) {
state = 4;
printf("test 4 \n");
}
else if (*(text + index) != *(pattern + 3) && state ==3) {
state = 0;
printf("test 4.4 \n");
}
else {
return -1;
}
index++;
}
return index;
}
#包括
#包括
char*getCharBlock（int*size）；
int findmatchA（字符*文本，字符*模式，int tsize，int psize）；
void printIt（字符*ptr，整数索引，整数大小）；
int main（）{
char*text，*pattern；//将要读取的字符的指针
char*p，*q，*r；//一些指针变量
int tsize，psize，x，y，z；//一些整数
printf（“请输入字符文本序列（仅存储字符）：”；
text=getCharBlock（&tsize）；
printf（“现在输入您要搜索的模式：”；
模式=getCharBlock（&psize）；
x=findmatch（文本、图案、tsize、psize）；
如果（x==-1）{
printf（“未找到匹配项”）；
printf（“不存在匹配的起始位置\n”）；
}
否则{
printf（“已找到匹配项！\n”）；
printf（“在索引%d\n”，x处匹配起始位置）；
printf（“匹配后的剩余文本：\n”）；
打印（文本，x+psize，tsize）；
}
免费（文本）；
自由（模式）；
}
char*getCharBlock（int*size）{
char*input=（char*）malloc（80*sizeof（char））；
字符a；
int i=0；
a=getchar（）；
虽然（i='a'&&a='a'&&a我没有阅读您的全部代码，但我只关注您的无限循环问题
findmatch（）函数中while循环的控制条件有问题。您正在检查psize中是否没有[x]。
数组可以被数组指针访问。所以状态[0]是数组中的第一个字符。状态==0，然后依次类推到状态==3，这很好，但需要处理数组。
我是诺布，不过差不多。
希望这会有所帮助
我知道这对你们中的大多数人来说都是基本的，我只是希望能尽快做到
成为一名更熟练的程序员
祝你好运，我给你提建议
有几个问题使程序无法正常运行
它以一种我不知道的方式陷入无限循环
明白
1） 您必须在此处执行以下操作：
`while (psize <= tsize) {`
这可能会妨碍正确的模式匹配
4） 未完成输入验证，例如：您应该确保模式的长度正好为4
个字符
如果我只被允许给你一个建议，那就是：“永远不要使用If-else链！”
。用开关盒断开结构替换它
您的int findmatch
就是一个完美的例子。如果else
的链造成难以调试的丛林。您的状态非常相似，应该会产生和谐。
它们不是。您的函数可以替换为更简单的函数：
int findmatch(char *text, char *pattern, int tsize, int psize) {
int index = 0;
int state = 0;
printf("Text=<%s> pattern=<%s> tsize=%d psize=%d \n",text, pattern, tsize, psize);
while (index <= tsize) {
switch (state)
{
case 0:
state = next_state(text,pattern, "test 1", "test1.1", &index, 0, 1, 1);
break;
case 1: // pattern[0] matched
state = next_state(text, pattern, "test 2", "test2.2", &index, 1, 2, 0);
break;
case 2: // pattern [0] [1] matched
state = next_state(text, pattern, "test 3", "test3.3", &index, 2, 3, 0);
break;
case 3: // pattern [0] [1] [2] matched
state = next_state(text, pattern, "test 4", "test4.4", &index, 3, 4, 0);
break;
case 4:
printf("DONE, index = %d \n",index);
return index;
break;
default:
printf("We should not be here! \n");
break;
} // case
} // while
return -1;
}
intfindmatch（char*text，char*pattern，inttsize，intpsize）{
int指数=0；
int state=0；
printf（“Text=pattern=tsize=%d psize=%d\n”，Text，pattern，tsize，psize）；
而（索引<代码>#包括
#包括
int-Myindex=0；
char*getCharBlock（int*size）；
int findmatchA（字符*文本，字符*模式，int tsize，int psize）；
int findmatchB（字符*文本，字符*模式，int tsize，int psize）；
int findmatchC（字符*文本，字符*模式，int tsize，int psize）；
void printIt（字符*ptr，整数索引，整数大小）；
int main（）{
字符*text、*pattern、*text2、*pattern2、*text3、，
*pattern3；//要读取的字符的指针
char*p，*r；//一些指针变量
int tsize，psize，tsize2，psize2，tsize3，psize3，x，y，z；//一些整数
printf（“\n”）；
printf（“请输入字符序列（只显示字符）”
“已存储）：\n”）；
text=getCharBlock（&tsize）；
printf（“\n”）；
//printf（“tsize是%d\n”，tsize）；
printf（“现在输入要搜索的模式：\n”）；
模式=getCharBlock（&psize）；
//printf（“tsize为%d\n”，psize）；
x=FindMatch（文本、图案、tsize、psize）；
如果（x==-1）{
printf（“\n”）；
printf（“未找到匹配项”）；
printf（“\n”）；
printf（“不存在匹配的起始位置\n”）；
}否则{
printf（“\n”）；
printf（“已找到匹配项！！！\n”）；
//printf（“%d\n”，x）；
printf（“\n”）；
printf（“在索引%d\n处匹配起始位置”，x-3）；
printf（“\n”）；
printf（“匹配后的剩余文本：\n”）；
打印（文本、x、T尺寸）；
}
////应该通过什么；
//查找匹配项，返回-1表示失败，或返回一个int，该int是要查找的索引
//匹配开始的位置。返回值可用于
//确定是否找到匹配项，以及在何处。
printf（“\n”）；
printf（“现在输入非连续字符的字符文本序列”
“匹配（仅存储字符）：\n”）；
text2=getCharBlock（&tsize2）；
printf（“\n”）；
printf（“现在输入要在非连续模式中搜索的模式”
“方式：\n”）；
模式2=getCharBlock（&psize2）；
y=findmatchB（文本2、模式2、tsize2、psize2）；
如果（y==-1）{
printf（“\n”）；
printf（“未找到匹配项”）；
printf（“\n”）；
printf（“不存在匹配的起始位置\n”）；
}否则{
printf（“\n”）；
printf（“已找到匹配项！！！\n”）；
printf（“\n”）；
printf（“在索引%d\n处匹配起始位置”，y-4）；
printf（“\n”）；
printf（“匹配后的剩余文本：\n”）；
打印（文本、y、T尺寸）；
}
printf（“\n”）；
printf（“现在输入多个字符的字符文本序列”
“匹配（仅存储字符）：\n”）；
text3=getCharBlock（&tsize3）；
printf（“\n”）；
printf（“现在输入要搜索的模式：\n”）；
pattern3=getCharBlock（&psize3）；
z=FindMatch（文本3，模式
`while (psize <= tsize) {`
else if (*(text + index) == *(pattern + 2) && state ==2) {
state = 3; // sg! index++; is missing!
printf("test 3 \n");
}
else if (*(text + index) != *(pattern + 2) && state ==2) {
state = 0;
printf("test 3.3 \n");
}
int findmatch(char *text, char *pattern, int tsize, int psize) {
int index = 0;
int state = 0;
printf("Text=<%s> pattern=<%s> tsize=%d psize=%d \n",text, pattern, tsize, psize);
while (index <= tsize) {
switch (state)
{
case 0:
state = next_state(text,pattern, "test 1", "test1.1", &index, 0, 1, 1);
break;
case 1: // pattern[0] matched
state = next_state(text, pattern, "test 2", "test2.2", &index, 1, 2, 0);
break;
case 2: // pattern [0] [1] matched
state = next_state(text, pattern, "test 3", "test3.3", &index, 2, 3, 0);
break;
case 3: // pattern [0] [1] [2] matched
state = next_state(text, pattern, "test 4", "test4.4", &index, 3, 4, 0);
break;
case 4:
printf("DONE, index = %d \n",index);
return index;
break;
default:
printf("We should not be here! \n");
break;
} // case
} // while
return -1;
}
#include <stdio.h>
#include <stdlib.h>
char *getCharBlock(int *size);
int findmatch(char *text, char *pattern, int tsize, int psize);
void printIt(char *ptr, int index, int size);
void printIt(char *ptr, int index, int size)
{
}
int main(void){
char *text, *pattern; // pointers for the characters you will read
int tsize,psize,x; // some integers
printf("Please input a sequence of character text (characters only will be stored):\n");
text = getCharBlock(&tsize);
printf("Now input the pattern you seek to search for: \n");
pattern = getCharBlock(&psize);
x = findmatch(text, pattern, tsize, psize);
if(x == -1){
printf("No Match Found \n");
printf("No starting position for match exists \n");
}
else{
printf("Match Has Been Found! \n");
printf("Match starting position at index %d \n", x - 4);
printf("Remaining text after Match: <%s> \n", text + x );
printIt(text, x+psize, tsize);
}
free(text);
free(pattern);
}
char *getCharBlock(int *size){
char *input = (char*) malloc (80*sizeof(char) +1 );
if (input == NULL)
{
printf("No memory!\n");
exit(-1);
}
char a;
int i = 0;
a = getchar();
while( i<80 && a != '\n'){
if( ((a>= 'a') && (a <= 'z')) || ( (a>= 'A') && (a <= 'Z') ) ){
* (input + i) = a;
i++;
}
a = getchar();
}
* (input + i) = 0; // sg7! terminate the string
*size = i;
return input;
}
int next_state(char *text, char *pattern, char *m1, char *m2, int *index, int patternInd, int next_state, int advInd )
{
int state = 0;
if (text[*index] == pattern[patternInd]){
state = next_state;
printf( "%s\n", m1);
(*index)++;
}
else{
printf( "%s\n", m2);
if(advInd)
(*index)++;
}
return state;
}
int findmatch(char *text, char *pattern, int tsize, int psize) {
int index = 0;
int state = 0;
printf("Text=<%s> pattern=<%s> tsize=%d psize=%d \n",text, pattern, tsize, psize);
while (index <= tsize) {
switch (state)
{
case 0:
state = next_state(text,pattern, "test 1", "test1.1", &index, 0, 1, 1);
break;
case 1: // pattern[0] matched
state = next_state(text, pattern, "test 2", "test2.2", &index, 1, 2, 0);
break;
case 2: // pattern [0] [1] matched
state = next_state(text, pattern, "test 3", "test3.3", &index, 2, 3, 0);
break;
case 3: // pattern [0] [1] [2] matched
state = next_state(text, pattern, "test 4", "test4.4", &index, 3, 4, 0);
break;
case 4:
printf("DONE, index = %d \n",index);
return index;
break;
default:
printf("We should not be here! \n");
break;
} // case
} // while
return -1;
}
Please input a sequence of character text (characters only will be stored):
aaabcdef
Now input the pattern you seek to search for:
abcd
Text=<aaabcdef> pattern=<abcd> tsize=8 psize=4
test 1
test2.2
test 1
test2.2
test 1
test 2
test 3
test 4
DONE, index = 6
Match Has Been Found!
Match starting position at index 2
Remaining text after Match: <ef>
Please input a sequence of character text (characters only will be stored):
abcdefgh
Now input the pattern you seek to search for:
efgh
Text=<abcdefgh> pattern=<efgh> tsize=8 psize=4
test1.1
test1.1
test1.1
test1.1
test 1
test 2
test 3
test 4
DONE, index = 8
Match Has Been Found!
Match starting position at index 4
Remaining text after Match: <>
#include <stdio.h>
#include <stdlib.h>
int Myindex = 0;
char *getCharBlock(int *size);
int findmatchA(char *text, char *pattern, int tsize, int psize);
int findmatchB(char *text, char *pattern, int tsize, int psize);
int findmatchC(char *text, char *pattern, int tsize, int psize);
void printIt(char *ptr, int index, int size);
int main() {
char *text, *pattern, *text2, *pattern2, *text3,
*pattern3; // pointers for the characters you will read
char *p, *r; // some pointer variables
int tsize, psize, tsize2, psize2, tsize3, psize3, x, y, z; // some integers
printf(" \n");
printf("Please input a sequence of characters (only characters will be "
"stored ): \n");
text = getCharBlock(&tsize);
printf("\n");
// printf( "tsize is %d \n", tsize);
printf(" Now input the pattern you seek to search for: \n");
pattern = getCharBlock(&psize);
// printf( "tsize is %d \n", psize);
x = findmatchA(text, pattern, tsize, psize);
if (x == -1) {
printf("\n");
printf("No Match Found \n");
printf("\n");
printf("No starting position for match exists \n");
} else {
printf("\n");
printf("Match Has Been Found!!! \n");
// printf( "%d\n", x);
printf("\n");
printf("Match starting position at index %d \n", x - 3);
printf("\n");
printf("Remaining text after Match: \n");
printIt(text, x, tsize);
}
// //what should be passed?);
// looks for a match, returns -1 for failure or an int which is the index to
// the location where the match starts. the return values can be used to
// determine IF a match was found, and where.
printf("\n");
printf("Now input a sequence of character text for non-contiguous "
"matching(characters only will be stored): \n");
text2 = getCharBlock(&tsize2);
printf("\n");
printf(" Now input the pattern you seek to search for in a non-contiguous "
"manner: \n");
pattern2 = getCharBlock(&psize2);
y = findmatchB(text2, pattern2, tsize2, psize2);
if (y == -1) {
printf("\n");
printf("No match found \n");
printf("\n");
printf("No starting position for match exists \n");
} else {
printf("\n");
printf("Match has been found!!! \n");
printf("\n");
printf("Match starting position at index %d \n", y - 4);
printf("\n");
printf("Remaining text after match: \n");
printIt(text, y, tsize);
}
printf("\n");
printf("Now input a sequence of character text for multiple "
"matchings(characters only will be stored): \n");
text3 = getCharBlock(&tsize3);
printf("\n");
printf(" Now input the pattern you seek to search for: \n");
pattern3 = getCharBlock(&psize3);
z = findmatchC(text3, pattern3, tsize3, psize3);
printf("\n");
printf("The Number of Matches Is %d \n", z);
free(text);
free(pattern);
free(text2);
free(pattern2);
free(text3);
free(pattern3);
}
char *getCharBlock(int *size) {
// this would fill in the "string" of chars for the passed in char pointer.
char *input = (char *)malloc(80 * sizeof(char));
char a;
int i = 0;
a = getchar();
while (i < 80 && a != '\n') {
if ((a >= 'a' && a <= 'z') || (a >= 'A' && a <= 'Z')) {
*(input + i) = a;
i++;
}
a = getchar();
}
*(input + i) = '\0';
*size = i;
return input;
}
int findmatchA(char *text, char *pattern, int tsize, int psize) {
int index = 0;
int state = 0;
while (psize <= tsize) {
if ((*(text + index) == *pattern) && state == 0) {
state = 1;
index++;
// printf( "test 1 \n");
}
else if ((*(text + index) != *pattern) && state == 0) {
state = 0;
index++;
// printf( "test1.1 \n");
}
else if (*(text + index) == *(pattern + 1) && state == 1) {
state = 2;
index++;
// printf( "test 2 \n");
}
else if (*(text + index) != *(pattern + 1) && state == 1) {
state = 0;
index++;
// printf("test 2.2 \n");
}
else if (*(text + index) == *(pattern + 2) && state == 2) {
state = 3;
index++;
// printf("test 3 \n");
}
else if (*(text + index) != *(pattern + 2) && state == 2) {
state = 0;
index++;
// printf("test 3.3 \n");
}
else if (*(text + index) == *(pattern + 3) && state == 3) {
state = 4;
index++;
return index;
// printf("test 4 \n");
break;
}
else if (*(text + index) != *(pattern + 3) && state == 3) {
state = 0;
index++;
// printf("test 4.4 \n");
}
else {
return -1;
}
}
return index;
}
int findmatchB(char *text2, char *pattern2, int tsize2, int psize2) { // non-
//contiguous case
int index = 0;
int state = 0;
while (psize2 <= tsize2) {
if ((*(text2 + index) == *pattern2) && state == 0) {
state = 1;
index++;
// printf("test1\n");
}
else if ((*(text2 + index) != *pattern2) && state == 0) {
state = 0;
index++;
// printf("test1.1\n");
}
else if (*(text2 + index) == *(pattern2 + 1) && state == 1) {
state = 2;
index++;
// printf("test2\n");
}
else if (*(text2 + index) != *(pattern2 + 1) && state == 1) {
state = 1;
index++;
// printf("test2.2\n");
}
else if (*(text2 + index) == *(pattern2 + 2) && state == 2) {
state = 3;
index++;
// printf("test3\n");
}
else if (*(text2 + index) != *(pattern2 + 2) && state == 2) {
state = 2;
index++;
// printf("test3.3\n");
}
else if (*(text2 + index) == *(pattern2 + 3) && state == 3) {
state = 4;
index++;
// printf("test4\n");
break;
return index;
}
else if (*(text2 + index) != *(pattern2 + 3) && state == 3) {
state = 3;
index++;
// printf("test4.4\n");
}
else {
return -1;
}
}
return index;
}
int findmatchC(char *text3, char *pattern3, int tsize3, int psize3) {
int index = 0;
int pindex = 0;
int state = 0;
int matchcount = 0;
// printf( "tsize is %d \n", tsize3);
while (index <= tsize3) {
// printf( "test of inside loop \n");
// printf( "pindex is %d \n", pindex);
// printf( "tindex is %d \n", index);
// printf( " text value is %c \n", *(text3 + index));
// printf( " pattern value is %c \n", *(pattern3 + pindex));
if (*(text3 + index) == *(pattern3 + pindex) && state == 0) {
state = 1;
index++;
pindex++;
// printf( "test 1 \n");
}
else if (*(text3 + index) != *(pattern3 + pindex) && state == 0) {
state = 0;
index++;
// pindex++;
// printf( "test1.1 \n");
}
else if (*(text3 + index) == *(pattern3 + pindex) && state == 1) {
state = 2;
index++;
pindex++;
// printf( "test 2 \n");
}
else if (*(text3 + index) != *(pattern3 + pindex) && state == 1) {
state = 0;
index++;
// pindex++;
// printf("test 2.2 \n");
}
else if (*(text3 + index) == *(pattern3 + pindex) && state == 2) {
state = 3;
index++;
pindex++;
// printf("test 3 \n");
}
else if (*(text3 + index) != *(pattern3 + pindex) && state == 2) {
state = 0;
index++;
// pindex++;
// printf("test 3.3 \n");
}
else if (*(text3 + index) == *(pattern3 + pindex) && state == 3) {
state = 0;
index++;
pindex = 0;
matchcount++;
// printf("test 4 \n");
}
else if (*(text3 + index) != *(pattern3 + pindex) && state == 3) {
state = 0;
index++;
pindex = 0;
// printf("test 4.4 \n");
}
else {
return -1;
}
}
return matchcount;
}
void printIt(char *ptr, int index, int size) {
while (index < size) {
printf("%c", *(ptr + index));
index++;
}
printf("\n");
}