From 5b9a183eea9c0ad576d6f1f693f6cbd70f212324 Mon Sep 17 00:00:00 2001
From: Dudeman <linuxluser@gmail.com>
Date: Mon, 4 May 2015 09:25:08 -0700
Subject: [PATCH] Update hw_getfile.cpp

In your while-loop, you need to check that `pos` is not -1. -1 means that the substring (`word` in this case) was not found on that line. ANY positive integer means that `word` was found and thus is a match. So you only need to test `pos` against the value -1.

I also put in a check for the number of arguments given. If somebody runs your program without arguments, you should give a helpful error message and exit non-zero. Without that check, your program was simply illegally accessing the array `argv` and being killed by the system for an "out of bounds" exception. A quick check against `argc` makes this common situation much prettier.
---
 hw_getfile.cpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw_getfile.cpp b/hw_getfile.cpp
index 108f669..46a6274 100644
--- a/hw_getfile.cpp
+++ b/hw_getfile.cpp
@@ -9,7 +9,10 @@ using namespace std;
 //~~~~~~~~~~~~~~~~~~~~prints line from target word on.
 int main(int argc, char* argv[]){
   
-  //for (int i = 0; i<argc; i++)
+  if (argc < 2) {
+    cerr << "ERROR: missing first argument" << endl;
+    exit(1);
+  }
   string word = string(argv[1]);
   
 
@@ -18,14 +21,14 @@ int main(int argc, char* argv[]){
   ifstream infile (fileName.c_str());
 
   if (infile.good() == false){
-    cout << "unable to open the file name." << fileName;
+    cerr << "ERROR: unable to open the file name " << fileName << endl;
     exit(1);
   }
 
   while(true) {
     getline(infile, line);
     size_t pos = line.find(word);
-    if (pos == 2){
+    if (pos != -1){
       string word = line.substr(pos);
       cout << word  << endl;
     }