Expert: Zlatko - 11/12/2009

Question
QUESTION: My syntax for the switch statement looks correct but I get case 2, 3, ... label not in switch statement.  I also need a function that finds the longest word in a file and returns the word and number of characters in the word to the function call.  So far my program looks like this.

#include <iostream>
#include <iomanip>
#include <fstream>

using namespace std;

//prototypes
//all parameters are strings, because
//input is taken from a file

int countW (string);
int countC (string);
int sumInt (string);
double avgInt (string);
int maxInt (string);
int minInt (string);
string wordL (string);

int main()
{
  ifstream inFile;
  int wordCount, charCount, intSum, choice;
  intMax, intMin;
  double intAvg;
  string fileName, lWord;
  
  do
  {  
    do
     {
      cout << "1. Count Words In a File" << endl;
      cout << "2. Count Characters In a File" << endl;
      cout << "3. Sum Integers In a File" << endl;
      cout << "4. Average Integers In a File" << endl;
      cout << "5. Maximum Integer In a File" << endl;
      cout << "6. Minimum Integer In a File" << endl;
      cout << "7. Longest Word In a File" << endl;
      cout << "8. Quit" << endl << endl;
    
      cout << "Choice :   ";
      cin >> choice;
      cout << "Enter the input file name:   ";
      cin >> fileName;
    
      
     
      inFile.open(fileName);
      if (inFile.fail())
      {
       cout << "Error opening input file --" << fileName
       << "please try again!" << endl;
      }
     }
    while (inFile.fail())
     
    
    switch(choice)        //function calls
    {
     case 1:  
         wordCount = countW(fileName);
         cout << "Word Count = " <<
         wordCount <<endl;
     
         break;          
        
     case 2:  
         charCount = countC(fileName);
         cout << "Char Count = " <<
         charCount << endl;
     
         break;
        
     case 3:  
         intSum = sumInt(fileName);
         cout <<"Sum of Integers = " <<
         intSum <<endl;
     
         break;
       
        
     case 4:  
         intAvg = avgInt(fileName);
         cout <<"Average of Integers = " <<
         intAvg << endl;
     
         break;
       
        
     case 5:
         intMax = maxInt(fileName);
         cout << "Maximum of Integers = "<<
         intMax << endl;
     
         break;
       
        
     case 6:  
         intMin = minInt(fileName);
         cout <<"Minimum of Integers = " <<
         intMin << endl;
     
         break;
       
        
     case 7:  
         lWord = wordL(fileName);
         cout << "Longest Word = " <<
         lWord << " characters" << endl;
     
         break;
       
     
     default:
         cout << "Invalid Input" << endl;
     
         break;
        
    }
  }
  while (option != 8)
  
  inFile.close();
  
  return 0;
}
//function definitions
int countW(string fileName)
{
int wordCount = 0;
string word;
ifstream inFile;
inFile.open(fileName.c_str());

inFile >> word;

while (inFile)
{
  wordCount = wordCount + 1;
  inFile >> word;
}

return wordCount;
}


int countC(string fileName)
{
 int charCount = 0;
 char character;
 ifstream inFile;
 inFile.open(fileName.c_str());
 
 inFile >> character;
 
 while (inFile)
 {
   charCount = charCount + 1;
   inFile >> character;
 }
 
 return charCount;
}


int sumInt(string fileName)
{
int intSum = 0, integer;
ifstream inFile;
inFile.open(fileName.c_str());

inFile >> integer;

while (inFile)
 {
   intSum = intSum + integer;
   inFile >> integer;
 }
 
return intSum;
}


double avgInt(string fileName)
{
 double intAvg;
 int integer, intSum = 0, number = 0;
 ifstream inFile;
 inFile.open(fileName.c_str());
 
 inFile >> integer;
 
 while (inFile)
  {
    intSum = intSum + integer;
    number = number + 1;
    inFile >> integer;
  }
 intAvg = intSum / number;
 
 return intAvg;

}


int maxInt(string fileName)
{
int intMax=0, num;
ifstream inFile;
inFile.open(fileName.c_str());
inFile >> num;

while (inFile)
{
  if (num > intMax)
  intMax = num;
  inFile >> num;
}

return intMax;
}


int minInt(string fileName)
{
int intMin, num;
ifstream inFile;
inFile.open(fileName.c_str());
inFile >> num;
intMin = num;

while (inFile)
{
  if (num <= intMin)
  intMin = num;
  inFile >> num;
}

return intMin;
}


string wordL(string fileName)
{
 string lWord, word;
 ifstream inFile;
 inFile.open(fileName.c_str());
 
 while (inFile)
  {
  
  }
 
 return lWord;
}
     
this last function will be to compute the longest word. It is incomplete.      


ANSWER: Chris, I corrected the syntax errors. My comments start with //---

I did not check any logic.

I'm not sure if you want me to do anything else. Can you take it from here ? Post a follow up question if you need more help.

#include <iostream>
#include <iomanip>
#include <fstream>
#include <string> //--- needed for cin >> string

using namespace std;

//prototypes
//all parameters are strings, because
//input is taken from a file

int countW (string);
int countC (string);
int sumInt (string);
double avgInt (string);
int maxInt (string);
int minInt (string);
string wordL (string);

int main()
{
   ifstream inFile;
   int wordCount, charCount, intSum, choice;
   int intMax, intMin; //--- always specify the type
   double intAvg;
   string fileName, lWord;

   do
   {  
       do
       {
         cout << "1. Count Words In a File" << endl;
         cout << "2. Count Characters In a File" << endl;
         cout << "3. Sum Integers In a File" << endl;
         cout << "4. Average Integers In a File" << endl;
         cout << "5. Maximum Integer In a File" << endl;
         cout << "6. Minimum Integer In a File" << endl;
         cout << "7. Longest Word In a File" << endl;
         cout << "8. Quit" << endl << endl;

         cout << "Choice :   ";
         cin >> choice;
         cout << "Enter the input file name:   ";
         cin >> fileName;



         inFile.open(fileName.c_str()); //--- need to send char* to open.
         if (inFile.fail())
         {
         cout << "Error opening input file --" << fileName
         << "please try again!" << endl;
         }
       }
       while (inFile.fail()); //--- in do/while, always end the while with a semicolon


       switch(choice)        //function calls
       {
       case 1:  
         wordCount = countW(fileName);
         cout << "Word Count = " <<
         wordCount <<endl;

         break;          

       case 2:  
         charCount = countC(fileName);
         cout << "Char Count = " <<
         charCount << endl;

         break;

       case 3:  
         intSum = sumInt(fileName);
         cout <<"Sum of Integers = " <<
         intSum <<endl;

         break;


       case 4:  
         intAvg = avgInt(fileName);
         cout <<"Average of Integers = " <<
         intAvg << endl;

         break;


       case 5:
         intMax = maxInt(fileName);
         cout << "Maximum of Integers = "<<
         intMax << endl;

         break;


       case 6:  
         intMin = minInt(fileName);
         cout <<"Minimum of Integers = " <<
         intMin << endl;

         break;


       case 7:  
         lWord = wordL(fileName);
         cout << "Longest Word = " <<
         lWord << " characters" << endl;

         break;


       default:
         cout << "Invalid Input" << endl;

         break;

       }
   }
   while (choice != 8); //--- changed option to choice

       inFile.close();

   return 0;
}
//function definitions
int countW(string fileName)
{
   int wordCount = 0;
   string word;
   ifstream inFile;
   inFile.open(fileName.c_str());

   inFile >> word;

   while (inFile)
   {
       wordCount = wordCount + 1;
       inFile >> word;
   }

   return wordCount;
}


int countC(string fileName)
{
   int charCount = 0;
   char character;
   ifstream inFile;
   inFile.open(fileName.c_str());

   inFile >> character;

   while (inFile)
   {
       charCount = charCount + 1;
       inFile >> character;
   }

   return charCount;
}


int sumInt(string fileName)
{
   int intSum = 0, integer;
   ifstream inFile;
   inFile.open(fileName.c_str());

   inFile >> integer;

   while (inFile)
   {
       intSum = intSum + integer;
       inFile >> integer;
   }

   return intSum;
}


double avgInt(string fileName)
{
   double intAvg;
   int integer, intSum = 0, number = 0;
   ifstream inFile;
   inFile.open(fileName.c_str());

   inFile >> integer;

   while (inFile)
   {
       intSum = intSum + integer;
       number = number + 1;
       inFile >> integer;
   }
   intAvg = intSum / number;

   return intAvg;

}


int maxInt(string fileName)
{
   int intMax=0, num;
   ifstream inFile;
   inFile.open(fileName.c_str());
   inFile >> num;

   while (inFile)
   {
       if (num > intMax)
         intMax = num;
       inFile >> num;
   }

   return intMax;
}


int minInt(string fileName)
{
   int intMin, num;
   ifstream inFile;
   inFile.open(fileName.c_str());
   inFile >> num;
   intMin = num;

   while (inFile)
   {
       if (num <= intMin)
         intMin = num;
       inFile >> num;
   }

   return intMin;
}


string wordL(string fileName)
{
   string lWord, word;
   ifstream inFile;
   inFile.open(fileName.c_str());

   while (inFile)
   {

   }

   return lWord;
}

---------- FOLLOW-UP ----------

QUESTION: I need to create a function that finds the longest word in a file and returns that word and the number of characters in the word to the function call.  I think there is a predefined function for it, but I can't find it in my text book or the internet.

It should look something like word.longest()
word represents a string variable.

Answer
Chris, if you consider a word to be characters delimited by spaces, then this function will do what you want.
You almost had it.


string wordL(string fileName)
{
  string lWord, word;
  ifstream inFile;
  inFile.open(fileName.c_str());

  while (inFile)
  {
      inFile >> word;
      if (word.length() > lWord.length())
      {
         lWord = word;
      }
  }

  return lWord;
}

int main(void)
{
   string longestWord = wordL("somefile.txt");
   cout << "The longest word is '" << longestWord << "' with length " << longestWord.length() << endl;
}