CODEWITHSUNDEEP
pythonc++
Yoshin
Yoshin

Reputation: 13

How can I split columns into a different vector

So there are 2 columns of these numbers:

1 10
2 -3
3 6
3 -6
1 -5

(data is taken from .txt) First column is number of client, second is balance I need to do operation like this. "for first client balance is equal to 10-5" "For second client client balance is equal to -3". How I can split columns to different for example vectors if I know how change account to vector this should be good. I know in Python it's gonna look something like this:

n = int(input())
account = [0]*100

for i in range(n)
    person, balance = input().split()
    person = int(person)
    balance = int(balance)
    account[person-1] += balance

for x in range(len(account)):
    if account[x] != 0:
        print(x+1, account[x]

But I need it in c++. I have something like this at this point. It should check how many accounts there is and show only 3 results.

ifstream file2("number.txt");

    vector<int> number;

    int input2;
    while(file2 >> input2)
    {
        number.push_back(input2);
    }

    int person=0,balance=0;
    int account[5];
    for (int i=0; i<number.size(); i+=2)
    {
        person=number[i];
        balance=number[i+1];
        account[person]+= balance;
    }
    for(int i=1; i<6; i++)
    {
        if(account[i]!=0)
        {
            cout << account[i] << endl;
        }
    }

Upvotes: 0

Views: 106

Answers (2)

KingEze
KingEze

Reputation: 79

if you are sure that for n clients all the clients ID respect 0 <= ID <= n:

  • you can just use a vector account to store your data, where the client i balance is stored at account[i]
ifstream file2("number.txt");
    vector<int> account;
    int person, balance;
    
    while (file2 >> person >> balance)
    {
        while (account.size() <= person) //making room for new client data 
            account.push_back(0);
        account[person] += balance; //saving client data
    }

    
    for (int i = 1; i < account.size(); i++)
        if (account[i] != 0)
            cout << account[i] << endl;

Otherwise :

  • you can use an unordered_map to store the client data
ifstream file2("number.txt");
    unordered_map<int,int> account;
    int person, balance;

    while (file2 >> person >> balance) {
        account[person] += balance;
    }

    for (auto& e : account)
        cout << e.first << " " << e.second << endl;

Upvotes: 0

Thomas Matthews
Thomas Matthews

Reputation: 57729

Often, a parallel array is an indication to use an array (vector) of struct:

struct Client
{
    int id;
    double balance;
};

The next step could be to overload operator>> to read in a Client instance:

struct Client
{
    int id;
    double balance;
    friend std::istream& operator>>(std::istream& input, Client& c);
};

std::istream& operator>>(std::istream& input, Client& c)
{
    input >> id;
    input >> balance;
    return input;
}

To input into a database:

std::vector<Client> database;
Client c;
while (input_file >> c)
{
    database.push_back(c);
}

You could do an search operation where the balance is -5.
Since floating point is not exact representation, we'll say that if the difference is less than 1.0E-5 the numbers are exact.

for (int i = 0; i < database.size(); ++i)
{
   double diff = abs(-5 - database[i].balance);
   if (diff < 1.0E-5)
   {
        break;
   }
}
if (i < database.size())
{
    std::cout << "Client " << database[i].id
              << ", balance: " << database[i].balance
              << "\n";
}

Upvotes: 1

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