Sum of data from a text file

Question

I'm trying to add numbers from a text file which looks like something like this :

player1
132
41

player2
1150
323

player3
60
2

The output should give something like this:

Where the second number of the pair would display the sum of the previous numbers' first number of the pair. However, I end up getting this:

The data seems to be displaying correctly but I don't understand why the sum isn't even though it's in the same loop. Here's my code :

#include <iostream>
#include <string>
#include <fstream>
using namespace std;

struct player{
string name;
int nbmatches;
int nbvictories;
};

player data;
int main(){

ifstream readFile;
readFile.open("note.txt");
if (readFile.fail()){
    cout << "not found" << endl;
}
else
{
    readFile.clear();
    while (!ws(readFile).eof()){
        readFile >> data.name
            >> data.nbmatches
            >> data.nbvictories;

        int totalvictories = 0;
        data.nbvictories += totalvictories;
        cout << data.nbvictories << endl;
        cout << totalvictories << endl;
        cout << endl;
    }
}
system("pause");
}

http://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong — Neil Kirk, Nov 09 '15 at 00:51
You are trying to do two things at once: read data from a file, and keep a running sum. Tackle them separately. — Beta, Nov 09 '15 at 00:55
you are adding zero to `data.nbvictories`. This is because you are initializing `totalvictories` in every iteration. — CroCo, Nov 09 '15 at 01:07

score 0 · Answer 1 · answered Nov 09 '15 at 01:09

0

"totalvictories" must be declred outside of while

int totalvictories = 0;
while (!ws(readFile).eof()){
    readFile >> data.name
        >> data.nbmatches
        >> data.nbvictories;

    data.nbvictories += totalvictories;
    cout << data.nbvictories << endl;
    cout << totalvictories << endl;
    cout << endl;
}

answered Nov 09 '15 at 01:09

blank_popup

231
2
9

Not only does `totalvictories` need to be initialized outside the loop, the line in the middle should be reversed: `totalvictories += data.nbvictories`. – Brian L Nov 09 '15 at 01:10
You could declare it as a static variable. Also, you can merge your two answers in one answer. – CroCo Nov 09 '15 at 01:30
You're right. I am not good at editing text. Thank you your concerning. – blank_popup Nov 09 '15 at 01:55

CroCo · Answer 2 · 2015-11-09T01:33:48.623

Your problem in the following code is

int totalvictories = 0; //<- a non-static variable with local scope 
data.nbvictories += totalvictories; //<- you are adding zero every iteration

This data.nbvictories is modified twice every iteration. Once when you assign it with the number you get from the file and the second with += which has not effect since totalvictories = 0. If totalvictories is supposed to store the total, then this variable should be modified not data.nbvictories, therefore, switch the statement to be totalvictories += data.nbvictories;

This is the code

#include <iostream>
#include <string>
#include <fstream>
using namespace std;

struct player{
string name;
int nbmatches;
int nbvictories;
};

player data;
int main(){

    ifstream readFile;
    readFile.open("note.txt");
    if (readFile.fail()){
        cout << "not found" << endl;
    }
    else
    {
        readFile.clear();
        while ( readFile >> data.name >> data.nbmatches >> data.nbvictories   ){

            //int totalvictories = 0;
            static int totalvictories = 0;
            //data.nbvictories += totalvictories;
            totalvictories += data.nbvictories; 

            cout << data.nbvictories << endl;
            cout << totalvictories   << endl;
            cout << endl;
        }
    }
    system("pause");

    return 0;
}

The result is

Extra: avoid using system("pause"); and eof().

score 0 · Answer 3 · answered Nov 09 '15 at 01:14

0

Move int totalvictories = 0 before your while loop, you are resetting it to 0 every iteration.

answered Nov 09 '15 at 01:14

Michael B.

145
1
8

Sum of data from a text file

3 Answers3