#include <iostream.h>
#include <fstream.h>          // for ifstream
#include <stdlib.h>           // for exit()
#include <ctype.h>            // for tolower()
#include <limits.h>           // for CHAR_MAX
#include "CPstring.h"
#include "prompt.h"
#include "vector.h"

// file: context.cc    DRAFT!!
// read text, as words, in program
// interactively, display requested word with C words before and after.
// author      Dietolf Ramm;  draft date: 10/30/96

const int C = 3; // number of words to display on either side
const string SENTINEL = "quit"; // word to cause exit from request loop
void Load(Vector<string> & text, int & size);
void Display(const Vector<string> & text, int size, string request);
int Find(const Vector<string> & text, int size, string request);

int main()
{
   int size;
   string request;
   Vector<string> text(500);

   Load(text, size);

   cout << "search word: ";
   cin >> request;
   while(request != SENTINEL)
   {
      Display(text, size, request);
      cout << "search word: ";
      cin >> request;
   }
   return 0;
}

int Find(const Vector<string> & text, int size, string request)
// postcondition: k points to matching word in text or returns -1
{
   int k;
   for (k = 0; k < size; k++)
      if (text[k] == request)
         return k;
   return -1;
}

void Display(const Vector<string> & text, int size, string request)
// postcondition: word located and printed in context or msg if not found
{
   int k, where;
   cout << request << " requested" << endl;
   where = Find(text, size, request);
   cout << where << " location" << endl;
   if (where >= 0)
   {
      for (k = where - C; k <= where + C; k++)
         cout << text[k] << " ";
      cout << endl;
   }
   else
      cout << " not found" << endl;
}

void Load(Vector<string> & text, int & size)
// postcondition: text contains words read in with size telling how many
{
   string word;
   string filename = PromptString("Enter name of input file: ");
   ifstream input(filename);

   size = 0;
   while (input >> word)
   {
      text[size] = word;
      size++;
   }
   cout << size << "words read." << endl;
}
    
Sample output:

context
Enter name of input file: context.cc
456words read.
search word: string
string requested
70 location
either side const string SENTINEL = "quit"; 
search word: main
main requested
-1 location
 not found
search word: main()
main() requested
108 location
string request); int main() { int size; 
search word: #include
#include requested
0 location
Illegal vector index: -3 (max = 500)
Assertion failed: index >= 0,
  file /usr/project/courses/cps008/lib/vector.h, line 191
Abort (core dumped)