Accelerated C++ "overriding commands for target"

[Madmartigan]

Gidday

Question : Write a program that will report the longest and shortest string in its input.

I am attempting EX 3.4(page 49) from Accelerated C++ by Koenig and Moo.

I keep getting the above mentioned compiler error and I'm not too sure what I'm doing wrong. Below is the source code. Please ignore the system("PAUSE") as I use this purely to pause the dos shell. Any pointers appreciated :

#include <iostream>
#include <string>
#include <vector>
#include <iomanip>
#include <ios>
#include <algorthim>
 
using std::cout;        using std::endl;        using std::cin;
using std::vector;      using std::string;      using std::setprecision;
using std::sort;        using std::streamsize;
 
int main()
{
  // ask for and read the users name  
  cout << "Please enter your name :";
  string name;
  cin >> name;
  cout << "Hello " << name << "!";
 
  // ask for and read names from the user
  cout << "Please enter a list of names, "
                  "followed by an end-of-file: ";
  vector<string> names;
  string x;
 
  // invariant: names contains all the names entered so far
  while (cin >> x) 
  names.push_back(x);
 
  // check that the user entered some names 
  typedef vector<string>::size_type vec_sz;
  vec_sz size = names.size();
  if (size == 0) {
      cout << endl << "You need to enter some names, "
                      "Please try again: " << endl;
      return 1;
  }
 
  // sort the names
  sort (names.begin(), names.end());
 
  // output the longest and shortest name
  streamsize prec = cout.precision();
  cout << "The shortest name is: " << setprecision(3)
       << names.begin() << "The longest name is: " << names.end();
       << setprecision(prec) << endl;
 
  system("PAUSE");    
  return 0;
}
 

[JosAH]

I think you're overcomplicatin g things a bit; why not simply keep track of the longest
and shortest strings read sofar? When you read a new string, compare it with
those two strings and update them where needed.

If you haven't read any strings yet you simply assign the currently read string
to both the shortest and the longest strings.

You don't need to sort anything or I must've misunderstood your question.

kind regards,

Jos

[Madmartigan]

I think you're overcomplicatin g things a bit; why not simply keep track of the longest
and shortest strings read sofar? When you read a new string, compare it with
those two strings and update them where needed.

If you haven't read any strings yet you simply assign the currently read string
to both the shortest and the longest strings.

You don't need to sort anything or I must've misunderstood your question.

kind regards,

Jos

Thanks Jos

I will look at another way to do this. I think I was under the impression that I had to use a vector in this way. I'm still a bit confused as to how to compare two strings with a new string entry.

Lannon

[JosAH]

Thanks Jos

I will look at another way to do this. I think I was under the impression that I had to use a vector in this way. I'm still a bit confused as to how to compare two strings with a new string entry.

Lannon

You don't have to compare strings; you just have to compare their lengths. There's
a member function for that purpose.

kind regards,

Jos

[Madmartigan]

Came up with this which works a treat. Thanks again


#include <iostream>
#include <algorithm>
#include <iomanip>
#include <ios>
#include <string>
#include <vector>

using std::cin; using std::sort;
using std::cout; using std::endl;
using std::string; using std::streamsize ;
using std::vector; using std::setprecisi on;

int main()
{
// ask for and read the user's name
cout << "Please enter your first name: ";
string name;
cin >> name;
cout << "Hello, " << name << "!" << endl;

// ask for and read family member's names
cout << "Please enter all your family members names, "
"followed by end-of-file: ";
vector<string> family;
string x;
// invariant:famil y contains all family names read so far
while (cin >> x)
family.push_bac k(x);

// check that the user entered some names
typedef vector<string>: :size_type vec_sz;
vec_sz size = family.size();
if (size == 0) {
cout << endl << "You must enter two or more family names. "
"Please try again." << endl;
system("PAUSE") ;
return 1;
}
// sort the names
sort(family.beg in(), family.end());
cout << endl;

// declare variable of type iterator to read through all elements
// declare min and max variables setting min to 100
int max = 0;
int min = 100;
for (vector<string> ::iterator i = family.begin(); i != family.end(); ++i)
{
if ((*i).length() > max) { // work out the longest name by testing
max = (*i).length(); //the length of each input against the last
}
if ((*i).length() < min) { //work out the shortest name by testing the
min = (*i).length(); //the length of each input against the last
}
}
cout << "Shortest family member name: " << min << endl;
cout << "Longest family member name: " << max << endl;


system("PAUSE") ;
return 0;
}

[JosAH]

Much better; well done.

A few minor nitpicks so that you can make this 'industrial strengh':

1) What if the user just enters one single name?
2) What if all the names are at least > 101 characters long?
3) Why are you still sorting that list?

kind regards,

Jos (<--- nitpicker, even in his spare time ;-)