可以帮我找下错误吗

#include "stdlib.h"
#include "stdio.h"
#include "string.h"

void lowercase_remove_punct(char *original_string, char *processed_string) {
    int i1, i2;
    char c;
    for (i1 = 0, i2 = 0; i1 < strlen(original_string); i1++) {
        c = original_string[i1];
        if ((c >= 'A') && (c <= 'Z'))
            processed_string[i2++] = original_string[i1] - 'A' + 'a';
        if (((c >= 'a') && (c <= 'z')) || (c == '\''))
            processed_string[i2++] = original_string[i1];
    }
    processed_string[i2] = '\0';
}

void BubbleSort(int* a, char** b, int length) {
    if (length > 1) {
        int j, k, t;
        char* temp;
        temp = (char*) malloc(20 * sizeof (char));
        while (1) {
            int flag = 0;
            j = 0;
            for (k = j + 1; k < length; j++, k++) {
                if (a[j] > a[k]) {
                    t = a[j];
                    strcpy(temp, b[j]);
                    a[j] = a[k];
                    strcpy(b[j], b[k]);
                    a[k] = t;
                    strcpy(b[k], temp);
                    flag = 1;
                }
            }
            if (flag == 0) break;
        }
    }
}

int main(int argc, char* argv[]) {
    FILE* in_file;
    in_file = fopen("textfile.txt", "r");
    char* in_string;
    char* out_string;
    char** store_string; 
 
    int* count_array;
    int end_of_file;
    store_string = (char**) malloc(500 * sizeof (char*));
    count_array = (int*) malloc(500 * sizeof (int));
    if (in_file == NULL) {
        printf("file open fail");
    } else {
        int num = -1;
        do {
            in_string = (char*) malloc(20 * sizeof (char));
            out_string = (char*) malloc(20 * sizeof (char));
            end_of_file = fscanf(in_file, "%s", in_string);
            if (end_of_file != EOF) {
                num++;
                lowercase_remove_punct(in_string, out_string);
                if (out_string[0] == '\0') {
                    num--;
                    continue;
                }
                store_string[num] = (char*) malloc(20 * sizeof (char));
                int i;
                int flag = 0;
                for (i = 0; i < num; i++) {
                    if (strcmp(store_string[i], out_string) == 0) {
                        flag = 1;
                        count_array[i]++;
                    }
                }
                if (flag != 1) {
                    strcpy(store_string[num], out_string);
                    count_array[num] = 1;
                } else {
                    num--; 
 
                }
            }
        } while (end_of_file != EOF);
        fclose(in_file);
        printf("All the words appeared without repeatation:\n");
        int p;
        for(p=0;p<=num;p++){
            printf("%s ", store_string[p]);
        }
        printf("\n");
        BubbleSort(count_array, store_string, num + 1);
        int k1, k2;
        printf("20 least words:\n");
        for (k1 = 0; k1 < 20; k1++) {
            printf("%s %d\n", store_string[k1], count_array[k1]);
        }
        printf("20 most words:\n");
        for (k2 = num; k2 > num - 20; k2--) {
            printf("%s %d\n", store_string[k2], count_array[k2]);
        }
    }
    return 0;
}

各位大神，帮我找下错误吧，。。文件打不开。有些地方也不知道有没有写对
[解决办法]
没仔细看你的程序内容，但如果是文件打不开，无非是文件名错误或路径不对，你核对一下。另外 ，程序有以下几个小建议
for (i1 = 0, i2 = 0; i1 < strlen(original_string); i1++)
中的strlen(original_string)运行次数太多，影响效率，建议另增加一个变量存放字符串长度；
同理 processed_string[i2++] = original_string[i1] - 'A' + 'a';
中'a' - 'A' 用一个变量代替；
in_file = fopen("F:\textfile.txt", "r"); 打开方式最好写明"rt"或"r+t"
store_string = (char**) malloc(500 * sizeof (char*)); 这个好像存不了什么数据，要用就直接用char二维数组，char*是指针的意思，其实是一个整形的占位长度，32位编译结果就是4个字节，500*4就是2000字节，应该不符合原意。
[解决办法]
LZ 我会跟你说用DEV-C++帮你debug了一下我蓝屏了吗 - -


重启后又运行了一下：

结果如下：

20 least words:
whatthefuck 1
bluescreen 1
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
(null) 0
20 most words:
bluescreen 1
whatthefuck 1
  

之后弹出错误，我就懒得继续看了…… 目测是文件读取代码不安全造成的