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Nov 13th, 2004

problem with Chars and Strings

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I have a problem which states that good people all have last names that be begin with the letters G through L; all the others are bad. The program must differentiate the good people from the bad. Does neone have any design ideas?

output:Name? Farley
Farley is a bad person

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boujibabe

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Nov 13th, 2004

Re: problem with Chars and Strings

>Does neone have any design ideas?
What is there to design? Read a string, check the first character, and print the appropriate message using an if statement and logical AND.

Narue

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Nov 13th, 2004

Re: problem with Chars and Strings

sorry i was just wondering if it could be done differently because mine isnt working

#include <iostream>
#include <string>

using namespace std;
int main()
{

//declare variables
string first="";
string name="";

//input items
cout<<"Name?";
cin>>name;
while (name!=0)
{
first.assign(name,0,1);
first=toupper(first);

if(first=='G'||first=='H'||first=='I'||first=='J'||first=='K'||first=='L')
cout<<first<<"is a good person"<<endl<<endl;
else
cout<<first<<"is a bad person"<<endl<<endl;
//endif

//input items
cout<<"Name?"
cin>>name;
}
//endwhile
return 0;
}
//end of main function

boujibabe

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Nov 13th, 2004

Re: problem with Chars and Strings

You're thinking too hard:

C++ Syntax (Toggle Plain Text)
#include <iostream>
#include <string>
 
using namespace std;
int main()
{
  //declare variables 
  string name;
 
  //input items
  while (cout<<"Name? ", cin>>name ) {
    if(name[0]=='G'||name[0]=='H'||name[0]=='I'||name[0]=='J'||name[0]=='K'||name[0]=='L')
      cout<<name<<" is a good person"<<endl<<endl;
    else
      cout<<name<<" is a bad person"<<endl<<endl;
    //endif 
  }
  //endwhile
  return 0;
}
//end of main function
#include <iostream>
#include <string>

using namespace std;
int main()
{
  //declare variables 
  string name;

  //input items
  while (cout<<"Name? ", cin>>name ) {
    if(name[0]=='G'||name[0]=='H'||name[0]=='I'||name[0]=='J'||name[0]=='K'||name[0]=='L')
      cout<<name<<" is a good person"<<endl<<endl;
    else
      cout<<name<<" is a bad person"<<endl<<endl;
    //endif 
  }
  //endwhile
  return 0;
}
//end of main function

Though that test chain is pretty long. You can tighten things up a bit by using a search string:

C++ Syntax (Toggle Plain Text)
#include <iostream>
#include <string>
 
using namespace std;
 
int main()
{
  string good ( "GHIJKL" );
  string name;
 
  while ( cout<<"Name? ", cin>>name ) {
    if ( good.find ( name[0] ) != string::npos )
      cout<< name <<" is a good person"<<endl<<endl;
    else
      cout<< name <<" is a bad person"<<endl<<endl;
  }
}
#include <iostream>
#include <string>

using namespace std;

int main()
{
  string good ( "GHIJKL" );
  string name;

  while ( cout<<"Name? ", cin>>name ) {
    if ( good.find ( name[0] ) != string::npos )
      cout<< name <<" is a good person"<<endl<<endl;
    else
      cout<< name <<" is a bad person"<<endl<<endl;
  }
}

Narue

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Nov 13th, 2004

Re: problem with Chars and Strings

Quote originally posted by Narue ...

>Does neone have any design ideas?
What is there to design? Read a string, check the first character, and print the appropriate message using an if statement and logical AND.

I know its a simple program but I am a beginner i just would like to know if there is nething I am doing wrong

boujibabe

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Nov 13th, 2004

Re: problem with Chars and Strings

I do agree that the test is pretty long but that method was shown to me by a tutor so i figured he would know best. Don't I have to find the first letter? one of the output samples lists the name Attila the Hun

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Re: problem with Chars and Strings

>i just would like to know if there is nething I am doing wrong
If it doesn't work then it's a safe bet you're doing something wrong. :rolleyes:

>shown to me by a tutor so i figured he would know best
Most of the tutors that I've seen don't know squat. But the test chain works; I was just showing you an alternative method.

>Don't I have to find the first letter?
name[0] is the first letter.

>one of the output samples lists the name Attila the Hun
Attila is the name of the person, the Hun is just a qualifier used to specify which Attila. However, you do have a distinct problem if this is one of the input strings. Using cin>>string causes the read to stop at whitespace, so you would only have "Attila" in name rather than "Attila the Hun". Further iterations of the loop would read "the" and "Hun", in that order. If you need to read lines instead of words, you want to use getline:

C++ Syntax (Toggle Plain Text)
while ( cout<<"Name? ", getline ( cin, name ) ) {
while ( cout<<"Name? ", getline ( cin, name ) ) {

By the way, wasn't Attila the Hun a "bad" person? If so, then the example works properly.

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Re: problem with Chars and Strings

the output does list Attila as a bad person when i tried th first one but i got sumthing like this
Name? Attila the hun
Attila the hun is a bad person

Name? the is a bad person
Name? hun is a bad person
Name?

lol

tutors don't know squat now isn't that ironic!

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Nov 13th, 2004

Re: problem with Chars and Strings

ps i 'm not sure if i'm comfortable placing the prompts in the actual while loop could they be placed outside aswell?

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Re: problem with Chars and Strings

>but i got sumthing like this
That's the problem I was talking about. Use getline to fix it.

>ps i 'm not sure if i'm comfortable placing the prompts in the actual while loop
To be perfectly honest, I haven't decided if it's good or bad style myself.

Convenient if the prompt is short, but I use it sparingly.

>could they be placed outside aswell?
Yes, but then you would have redundant prompts:

C++ Syntax (Toggle Plain Text)
cout<<"Name? ";
while ( cin>>name ) {
  if ( good.find ( name[0] ) != string::npos )
    cout<< name <<" is a good person"<<endl<<endl;
  else
    cout<< name <<" is a bad person"<<endl<<endl;
  cout<<"Name? ";
}
cout<<"Name? ";
while ( cin>>name ) {
  if ( good.find ( name[0] ) != string::npos )
    cout<< name <<" is a good person"<<endl<<endl;
  else
    cout<< name <<" is a bad person"<<endl<<endl;
  cout<<"Name? ";
}

That's not necessarily a bad thing though, and you can get around it with an infinite loop construct:

C++ Syntax (Toggle Plain Text)
while ( true ) {
  cout<<"Name? ";
  if ( !( cin>>name ) )
    break;
  if ( good.find ( name[0] ) != string::npos )
    cout<< name <<" is a good person"<<endl<<endl;
  else
    cout<< name <<" is a bad person"<<endl<<endl;
}
while ( true ) {
  cout<<"Name? ";
  if ( !( cin>>name ) )
    break;
  if ( good.find ( name[0] ) != string::npos )
    cout<< name <<" is a good person"<<endl<<endl;
  else
    cout<< name <<" is a bad person"<<endl<<endl;
}

Whether that's better or not is up to you. Loop structuring is a tricky business with all of the structured programming freaks running around out there.

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