在文本文档中查找数据的应用---C语言+dos

#include<stdio.h>
#include<stdlib.h>
#include<windows.h>
#include<conio.h>
#include< string.h>
int main()
{
     char string_to_be_find[ 100];
     while( true)
    {
         char find[ 100]= " find /I d:\\查找题目专用文档--随时更新--ma6174.txt \" ";
        printf( " \t\t题目查找专用程序   BY ma6174\n\n ");
        printf( " 请输入要查找的题目名： ");
        gets(string_to_be_find);
         if(strlen(string_to_be_find)== 0)
        {
            system( " cls ");
             continue;
        }
        strcat(find,string_to_be_find);
        strcat(find, " \" ");
        system(find);
        printf( " 是否将题目名加入文档？(y/n) ");
         char choice=getche();
         if(choice== ' y '||choice== ' Y ')
        {
             char write_in_file[ 100]= " echo  ";
            strcat(write_in_file,string_to_be_find);
            strcat(write_in_file, "  >>d:\\查找题目专用文档--随时更新--ma6174.txt ");
            system(write_in_file);
            printf( " \n\n题目名已经写入！ ");
            Sleep( 2000);
        }
        system( " cls ");
    }