My array question

Hello, im trying to write a program that takes the names of people, on a ranked external list, from there if a user types in a name if its on the list it displays it, with its rank. I think using an array would be best. but im not quite sure how to start tackling this.

Im not really good with filing handling, im trying to figure out how to have it search the code for the specific letters or names typed in.

this is all in C++ Thanks!

well if the data is already stored in the file formatted like
"name rank
name rank
name rank
....etc"

then you can easily create a class or struct that encapsulates that data, then store it in a vector of that type. To output based on the input criteria you can use the for_each algorithm to output only those that match the given input

http://www.cppreference.com/cppalgorithm/for_each.html

An array or vector would probably be a good storage model. Vector has the advantage of you not having to worry about the size.

Or, if you use std::map<>, you could use the name as a key, and the rank as the second element, thus avoiding you having to make a search yourself.

As general advice: Don't try to write the whole program at once. Portion up the work, so you do (for example) the code to read the names + ranks into an array [or vector, map or some such]. Once you have that working, start working on asking the user for a name, then work on the searching and listing.

--
Mats

Thank you for the reply s im going to start working on this in sections, typically its chaotic because i write it all, it half works and then i debug it.

Quote:

---

#include <fstream>
using std::ifstream;
using std::ofstream;
using std::ostream;

int main()
{

int Nums[999], x=0; ifstream inFile("babynames2004.txt"); //Open text file
while(inFile >> Nums[x] && x<50)

x++;

inFile.close(); return 0;

}

---

the txt file contains a list of integers, this code will read them into the array. okay so there are a 1000 names in this file. So this makes it a little easier.

My question is: 1) how do i make it so it read the entire line into the array?
2) how to make the search for it? based on user input.

Now that i think about this it wont work cause i need people to search for names and have it display the name and its rank. For example heres is 1 -10 rank names

1 Jacob Emily
2 Michael Emma
3 Joshua Madison
4 Matthew Olivia
5 Ethan Hannah
6 Andrew Abigail
7 Daniel Isabella
8 William Ashley
9 Joseph Samantha
10 Christopher Elizabeth

So when they type in a name, say its ethan or something, then it would output
ethan is ranked 5 in popularity among boys.
ethan is not ranked among the girls.

So would this be the right way to read each word in a line?

Code:

---

    int number;
    char boy, girl;
    ifstream names_txt;
    names_txt.open ( "babynames2004.txt" );
   
    names_txt >> number;
    names_txt >> boy;
    names_txt >> boy;

---

Still need to figure out how to have it search

why to allocate 999 ints if you plan to read only 50?
why not to use std::vector?
use getline to read a string (better into std::string )
you can use std::stringstream to parse the string if you need it

Yeah im not using that method at all, it doesnt make sense to me, i edited my other post.

char boy will held 1 character, are you sure it is enogh?
use std::string

Code:

---

    int number;
    char boy[20], girl[20];
    ifstream names_txt;
    names_txt.open ( "babynames2004.txt" );
   
    names_txt >> number;
    names_txt >> boy;
    names_txt >> girl;

---

Thanks for catching that. but is this right way to read each line?

i would write it like

Code:

---

int number;
std::string boy, girl;
std::ifstream names_txt( "babynames2004.txt" );

names_txt >> number;
names_txt >> boy;
names_txt >> girl;

---

Okay, and that would store the entire name no matter what length? so for example lets look at the first line

1 Jacob Emily

it would see from
names_txt >> rank; the first number 1.
then names_txt >> boy; would see Jacob
and names_txt >> girl; would see Emily?

Quote:

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would see

---

will contain - yes, and yes size is no matter here
operator >> will read till the wightspace

Okay good, so far i have that right. Now i need to build around this a way for a user to input data so maybe something like

Code:

---

cin >> boy, girl;

---

This so if they enter a name it will look at both those strings.

So i probally should use a loop to contiune running the code

Code:

---

    names_txt >> number;
    names_txt >> boy;
    names_txt >> girl;

---

Then if it finds a match output it.

What do you think?

Quote:

---

cin >> boy, girl;

---

no this will not work...

something like

Code:

---

cin >> name;
if ( name == boy)
{
// it's a boy name
}
else if (name == girl)
{
//it's a girl name
}
else
{
//it's a wrong name
}

---

and if you plan to search several names one after anouther - I world make a struct

Code:

---

struct Record
{
 int index;
 std::string boy;
 std::string girl;
};

---

and fill the
std::vector<Record>
with data from file - then I'll be able to search for the name in this vector without rereading the file again

Honestly i never used a vector for anything, i have no clue how to use them.

How would i fill the std::vector<Record>?

to add one record to the vector you can use

Code:

---

        struct Record
        {
                int index;
                std::string boy;
                std::string girl;
        };

        Record temp ={1,"Henry", "Wilma"};

        std::vector<Record> list;
        list.push_back(temp);

        std::cout << list[0].index << " " << list[0].boy << " " << list[0].girl << std::endl;

---

okay, so then after that i would need to have my

Code:

---

std::ifstream names_txt( "babynames2004.txt" );

---

right?

So would i use a loop to go through the vector or is there a different way since its a vector?

Is there a way to not use a vector and use an array? Im way to new to programming and i really dont understand vectors.

Quote:

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Is there a way to not use a vector and use an array?

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yes there is

Quote:

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Im way to new to programming and i really dont understand vectors.

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that's why you should go with vector - there is a lot more ways to screw up with arrays, vector does all memory menagement for you

Well basically i have a list with rank boy name and girl name.
example line would be like
1 Jacob Emily

i want the user to enter a name, and it would display like

name is rank 1 in boys
name is not ranked in girls

something like that, i couldn't even begin to work with a vector cause i have zero knowledge, i have been reading about them while posting here trying to understand, but im not sure if i even could, thats why i suggested arrays since ive have written a few basic programs with them. If i were to use vectors i would really need step by step advice. Which would be great if you are willing too :)

If not i understand, and ill try to screw around with it using arrays and probably ask for advice about that here as well

I have shown a sample how you add value to vector
to access element - there is no differens from array

Code:

---

        std::vector<int> arr;
        arr.push_back(1);
        arr.push_back(2);
        arr.push_back(3);

        for(std::vector<int>::size_type i = 0; i < arr.size(); i++)
        {
                std::cout << arr[i] << std::endl;
        }

---

Can you explain that line by line, im realyl having trouble understanding what is going on with what you are posting.

Code:

---

std::vector<int> arr; //declare a vector of ints
        arr.push_back(1); // add 1 to the vector's end
        arr.push_back(2); // add 2 to the vector's end
        arr.push_back(3); // add 3 to the vector's end

        std::vector<int>::size_type i; // declare the index var to be of type returned by size() function

        //size() function shows number of elements contained in the vector
        for(i = 0; i < arr.size(); i++) // loop through all vector's elements
        {
                std::cout << arr[i] << std::endl; // print current element
        }

        //same loop could be done using iterators - search forum for samples

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Thanks for all you help vart, i got it all finished, using ideas you gave me on how to structure it. I didnt use vectors though. I thank you for your time and patience