Searching through a file for a inputted string, and grabbing following information

Cyrus Bellefeuille 0
Viewed 37

So. I have not found good documention online about my question. I have a file, "Item Documentation.txt" Ignore the // comments, those will not be there later

0001 //Item ID
5.67 //Item Price
Eggs 12x //Item Name

0002
3.12
Milk Whole Gallon

I want to make a program to search for the Item ID, and then grab the following item price as a double and item name as a string. How could this be done.

I need to preface that I am very much still learning c++.

search file c++
1 Answers

You will want to use std::getline(some_open_file, some_string). Assuming you do not care for efficiency, you can simply check every line in the file against your item ID, then output the following line.

#include <fstream>

using string = std::string;

int main() {

  string item_id;
  string some_string;
  double item_price;
  string item_name;
  std::ifstream some_file("Item Documentation.txt");

  while (std::getline(some_file, some_string)) { // place the input into a string
    if (some_string == item_id) {
      std::getline(some_file, some_string); // grab the item price following it
      item_price = std::stod(some_string); // std::stod will extract a double from your string
      std::getline(some_file, some_string); // pulls the item name following that
      item_name = some_string;
      break;
    }
  }
  // then simply process your data here, outside the loop
  //
  return 0;
}

This works because every time getline() is called, it goes to the next line in the file.

Alternatively, you could place all your items into some data structure using the same while loop without the if statement, then simply use the builtin comparators to check for your item ID.

konray0
Related