need help on c-strings

fidelljf · #1 01-Dec-2005, 22:40

I'm working on a problem where the user inputs the first name, middle name and last name and should produce the output, last name, first name then midde initial.
example:

input: John Smith Doe

output: Doe, John S.

the program should also work even if the user does not put the middle name.
example:

input: John Doe
output: Doe, John

So far my program takes care only of the first example and I can't figure out on how to take care of the second example.
So far here is what I got.

CPP / C++ / C Code:

#include "stdafx.h"
#include <string>
#include <iostream>
using namespace std;


int main()
{ using namespace std;

	string first_name, middle_name, last_name;
	

	cout << "Enter your first name, middle name or initial and last name in that order\n";
    cin >> first_name >> middle_name >> last_name;
    cout << endl;
	cout << last_name << ", " << first_name << " " << middle_name[0] << "." << endl;
	
	return 0;
}

Paramesh · #2 02-Dec-2005, 01:13

Hi fidel,

Welcome to GIDForums.

The second example is somewhat complicated.
Dont worry.We'll discuss how to do it.

We do not know whether the user will enter three names or not.
So, the better option is get the entire line the user enters.

This can be done using getline function.

CPP / C++ / C Code:

    string line;
    getline(cin, line);

The next step is to calculate how many strings are there in the line.
If there is only two strings, we understand that the user has not entered the middle name.
If there is three strings, the user has entered all of his names.
We are using an array of strings instead of separate names. this helps in easy coding.

CPP / C++ / C Code:

    string name[3];

Then we should initialize each of the strings like this:

CPP / C++ / C Code:

    name[0]="";
    name[1]="";
    name[2]="";

Consider that 'j' is a variable that indicate the current name.
If j is 0, then name[j] indicates the first name.
if j is 1, name[j] indicates the second name, and
if j is 2, name[j] indicates the third name.
So, initialize j to zero at the start.

Next, how to find out that how many strings are there in the line?
Here comes the problem.
We should check character by character in string line.

For example, consider that the user enters this:

Code:

John Doe

So,

In a loop, where 'i' varies from 0 to line.length():
check whether character line[i] is a space.
if it is a space, then increment j.
Else, it is not a space, and add line[i] to name[j].
end loop.

Something Like this:

CPP / C++ / C Code:

    for(i = 0, j = 0; i < line.length(); i++)
    {
        if( line[i] == ' ' )
            j++;
        else 
            name[j] += line[i];
    }

Then, in the end, check whether j is 0, 1 or 2.
If j is 1, the user has only entered his first name. So, print name[0].
else if j is 2, the user has entered first and last names only. So, print name[0] and name[1].
else, j is 3. So the print name[0], name[1] and name[2].

Note that this is a simple program, that works only if the user enters three strings with only one space between them.
Like this:

Code:

John Smith Doe

Suppose that the user enters like this:

Code:

John    Smith Doe

Now, the program fails!
Because we have not checked for multiple spaces inbetween the words.

What can we do now?

We should increment j only once in multiple spaces that occurs in line.

So, we should increment j only if:
1. present character line[i] is a space, and
2. previous character should not_be_equal to a space.

Regards,

Paramesh.

fidelljf · #3 02-Dec-2005, 15:47

thanks a lot Paramesh

fidelljf · #4 02-Dec-2005, 17:04

im still having problems. somehow it would not display the desired results

CPP / C++ / C Code:

#include "stdafx.h"
#include <string>
#include <iostream>
using namespace std;


int main()
{ using namespace std;

	




    string line;

    string name[3];


	name[0]="";
	name[1]="";
	name[2]="";


    cout << "Enter your first name, middle name or initial and last name in that order\n";
    getline(cin, line);

	

	
    	for(int i = 0, int j = 0; i < line.length(); i++)
    {
        if( line[i] == ' ' )
            j++;
        else 
            name[j] += line[i];
	}

    
    

        if(j=1)
	{
		cout << name[0] << endl;
	}

	else if (j=2)
	{
		cout << name[1] << ", " << name[0] << endl;
	}

	else
	{
		cout << name[2] << ", " << name[0] << " " << name[1][0] << "." << endl;
	}

    
	cout << endl;
 
	

	
    cout << endl;
	
	
	return 0;
}

//Then, in the end, check whether j is 0, 1 or 2.
//If j is 1, the user has only entered his first name. So, print name[0].
//else if j is 2, the user has entered first and last names only. So, print name[0] and name[1].
//else, j is 3. So the print name[0], name[1] and name[2].

Paramesh · #5 02-Dec-2005, 18:15

Hi fidel,

You cant do like this: (in the for loop)

CPP / C++ / C Code:

int i = 0, int j = 0;

And since you want to use j later in the program, you can declare them at the start itself.
Like this:

CPP / C++ / C Code:

int main()
{
    int i = 0, j = 0;
   //code....

Next, My typing fault:
Then, in the end, check whether j is 0, 1 or 2.

And should use double quotes when you are checking conditions.
Like this:

CPP / C++ / C Code:

        if(j==0)

With that change, the first hurdle is over.!

Regards,

Paramesh.

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