[SOLVED] pulling out 27

dugan · 12-18-2023, 10:35 AM

When you read the data from the file, it's a string. Leave it as a string. And you don't need a regular expression; you just need a substring search.

Code:

#include <iostream>

int main()
{
    std::string number{"120027000"};

    if (number.rfind("27") < number.length() - 3)
    {
        std::cout << "It has a 27 in the right place\n";
    }
    return 0;
}

dugan · 12-18-2023, 10:37 AM

Quote:

Originally Posted by Turbocapitalist

Then the Lua based regexp module for C++ is described here:

http://www.gammon.com.au/forum/?id=11063

I have a better link:

https://en.cppreference.com/w/cpp/regex

michaelk · 12-18-2023, 11:17 AM

Quote:

When you read the data from the file, it's a string.

Not necessarily, granted we don't know how the OP is reading data from the file but you can easily read from an ASCII file as integers with spaces as a separator.

Quote:

int a,b,c,d;
fscanf(file,"%d %d %d %d",&a, &b, &c, &d);

rtmistler · 12-18-2023, 02:54 PM

Quote:

Originally Posted by atjurhs

NevemTeve and Michaelk, thank you very much! surprisingly simple. i was doing the division and the mod in the wrong order and i didn't know that the % sign in c++ means mod. i've got a lot to learn in c++ guess i could have found that on google

WTHeck you doing math for?

ASCII string, pull out one line as a time into a char buffer, use a char * to point to [2] and [5] check if they're zeros.
If so, pull out [3][4] otherwise continue and stop at EOF

atjurhs · 12-19-2023, 10:01 AM

Quote:

Originally Posted by rtmistler

WTHeck you doing math for?

i'm doing math because it's the only way i know how to begin to write the code - i'm a complete beginner at this coding stuff, please be nice.

the problem has been solved at this thread can be closed

rtmistler · 12-19-2023, 12:40 PM

Quote:

Originally Posted by atjurhs

i'm doing math because it's the only way i know how to begin to write the code - i'm a complete beginner at this coding stuff, please be nice.

the problem has been solved at this thread can be closed

Yeah sorry not intending to insult. Just exasperation at the overdone method.

Threads are not closed, replies can come at any future point, but usually people will leave old threads alone.

For learning purposes my suggestion is to consider multiple solution concepts, a very common point that sent me down frustration holes in early programming was single focus that my original concept to solve something was "the way", once you witness others solve things differently you begin to realize that your first instinct may not always be the right choice. There can be numerous "right" choices.

The syntax is easy, it's how you solve it which is the art form. And I hope you embrace that mindset, is my input here.