The problem is that i have to read a file that includes:

 type     count    price

bread      10       1.2 
butter      6       3.5
bread       5       1.3
oil        20       3.3
butter      2       3.1
bread       3       1.1

I have to use Vector Pair to read the file and to multiply the count and price and the output should be :

oil     
66
butter 
27.2
bread   
21.8

Any idea would be highly appreciated!

CodePudding user response：

If you only want to use std::pair and std::vector then you could use the following program as a starting point(reference):

#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>
int main()
{
    std::ifstream inputFile("input.txt"); //open the file
    std::string line; 
    
    std::vector<std::pair<std::string, double>> vec;
    
    std::string name;
    double price, count;
    
    if(inputFile)
    {   std::getline(inputFile, line, '\n');//read the first line and discard it
        while(std::getline(inputFile, line, '\n'))//read the remaining lines
        {
            std::istringstream ss(line);
            ss >> name; //read the name of the product into variable name
            ss >> count;//read the count of the product into variable count
            ss >> price;//read the price of the product into variable price
            
            vec.push_back(std::make_pair(name, count * price));
        }
    }
    else 
    {
        std::cout<<"File cannot be opened"<<std::endl;
    }
    inputFile.close();
    
    //lets print out the details 
    for(const std::pair<std::string, double> &elem: vec)
    {
        std::cout<< elem.first<< ": "<< elem.second<<std::endl;
    }
    return 0;
}

You can/should instead use a class or struct instead of using a std::pair.

The output of the above program can be seen here. The input file is also attached in the above link.