[求助]C程序算法

各位大侠看看这个程序哪里毛病没有,调试不好,不知道哪里要修改
＃i nclude <stdio.h>
＃i nclude <stdlib.h>
＃i nclude <string.h>
＃i nclude <time.h>
//获得prefix数组
int* GetPrefixValue(char* strPattern, int iPatternLen)
{
int i, j; /* i runs through the string, j counts the hits*/
int* prefix = (int*)malloc(iPatternLen*sizeof(int));

i = 1; j = 0;
prefix[0] = 0;

while(i<iPatternLen)
{
if(strPattern == strPattern[j])
{
prefix = ++j;
}
else
{
j = 0;
prefix = j;
}

i++;
}

return prefix;
}
//返回target串在pattern串中第一次匹配的index
int KMPStringMatch(char* strPattern, int iPatternLen, char* strTarget, int iTargetLen, int* prefix)
{
int i = 0;
int j = 0;

while(i<iPatternLen && j<iTargetLen)
{
if(j==0 || strPattern==strTarget[j])
{
i++; j++;
}
else
{
j = prefix[j];
}
}

free(prefix);

if(j==iTargetLen)
{
return i-j;
}
else
{
return -1;
}
}
int KMP(char* strPattern, char* strTarget)
{
int* prefix = GetPrefixValue(strPattern, strlen(strPattern));
int index = KMPStringMatch(strPattern, strlen(strPattern), strTarget, strlen(strTarget), prefix);
return index;
}
//在文本文件中查找target串出现的行数
int SearchInTxtFile(char* fileName, char* strTarget)
{
FILE* hFile = fopen(fileName, "r";

char str[1024];
int count = 0;


while(fgets(str, 1024, hFile))
{
if(KMP(str, strTarget)!=-1)
{
count++;
}
}

fclose(hFile);
hFile=NULL;

return count;
}

int main()
{
char ch;
char str1[] = "abcabcabctasksb,abTo";
char str2[] = "abc";

double t=clock();
printf("%d\n", KMP(str1,str2));
printf("耗时：%f毫秒！\n", (clock()-t));

t=clock();
printf("find %d \n", SearchInTxtFile("c:\\txt.txt", "NULL");
printf("耗时：%f毫秒！\n", (clock()-t));
scanf("%c", &ch);
return 0;
}
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