Why does C++ read values wrong from txt files?

Question

I have made a program that reads value from txt file "database.txt", but output is wrong when the number is three digit

ifstream myfile("database.txt");
int broj_rijeci = 0;
if (myfile.is_open())
{
    while (getline(myfile, line))
    {
        if (line.at(0) == '[')
        {
            int i = line.length() - 2;
            int brojac = 0;
            system("pause");
            while (line.at(i) != line.at(0))
            {
                input = line.at(i);
                ascii_convert(input);
                broj_rijeci = broj_rijeci + input * pow(10, brojac);
                i--;
                brojac++;
            }
        }
    }
    myfile.close();
}
else cout << "Unable to open file";

and my database looks like this:

[311]

output is "310"

Answer 1

Since you haven't provided the implementation of ascii_convert it's difficult to tell if the problem is there or elsewhere. However you can greatly simplify the process and eliminate the need for your own conversion routines by using std::stringstream.

#include <sstream>

std::ifstream myfile("database.txt");
if (myfile.is_open())
{
    std::string line;
    while (std::getline(myfile, line))
    {
        if (line.size() > 1 && line[0] == '[' && line[line.size() - 1] == ']')
        {
            int value;
            if(std::istringstream(line.substr(1, line.size() - 2)) >> value)
            {
                // Conversion was a success ... do something with "value"
            }
            else
            {
                // Conversion failed. Handle error condition.
            }
        }
    }
    myfile.close();
}
else std::cout << "Unable to open file";