thank you

I can understand that is is all new to you, and that it is difficult to grasp it all, but why use char array when there is a string class? Why do you refuse to read or look up documentation?
You do #include <string> so why don't you use it?

i doesn't return to loop ,, how can i do??

i got a result:::

#include <fstream>
#include <iostream>
#include <string>
using namespace std;

int main()
{
const int i=20;
char word[i];
int Counter;
cout<<"Enter word to search \n";
cin.get(word,i);


char fileName[80];
string buffer; // for user input
cout << "Enter file name: ";
cin >> fileName;


ifstream fin(fileName);
if(!fin.is_open())
{
cout << "Unable to open file";
system("pause");
exit(1);
}

Counter=0;
while(fin!='\0')
{
getline(fin,buffer);

size_t a = buffer.find(word,0);
if (a != string::npos)
{
cout<<buffer<<endl;
Counter++;
size_t b = a + 1;
a = buffer.find (word, b);
}
}
if(Counter>1)

cout << "Total "<<Counter<<" tLines\n";
else
cout << "Total "<<Counter<<" Line\n";
system("pause");
return 0;
}
____________________________________________

So,how can i link this program to dos??

that should be , because word[i] is a char, and word is a char array
Likewise this should be , otherwise you are comparing the first character only, and not the whole word

you cant enter the char array as

You should get the charter array char by char so Use

Here you must enter 30 chars exactly.