Getting data from every for loop - c++

Question

I want to output every data that I entered in the for loop in a tabular form. Unfortunately, the output only displays the last set of data that I entered. Any solution to solve this?
#include <iostream>
using namespace std;
int main()
{
double voltage, rpm, current, range;
int total; // total set enter by user
cout << "Please enter how many sets of data you want to calculate:";
cin >> total;
cout << "\n";
for(int i=1; i<=total; i++)
{
cout << "Enter he voltage " << i << ":";
cin >> voltage;
cout << "Enter the current " << i << ":";
cin >> current;
cout << "Enter the rpm " << i << ":";
cin >> rpm;
cout << endl;
double range = (voltage*1.2) + (current*0.5) + (rpm* 0.2);
}
cout << "Voltage\t\tCurrent\t\tRPM\t\tRange\n";
for(int i=1; i<=total; i++)
{
cout << voltage << "\t\t" << current << "\t\t" << rpm
<< "\t\t" << range << endl;
}
return 0;
}

Answer 1

This variables
double voltage,rpm,current,range;
each can only store a single double. To store many doubles, use a std::vector<double>:
#include <iostream>
#include <vector>
using std::cout;
using std::cin;
int main()
{
std::vector<double> voltages;
int total; //total set enter by user
cout << "Please enter how many sets of data you want to calculate:";
cin >> total;
cout << "\n";
for(int i = 1; i <= total; i++)
{
double voltage;
cout << "Enter he voltage " << i << ":";
if (cin >> voltage) {
voltages.push_back(voltage);
} else {
cout << "invalid input. Try again \n";
}
}
cout << "Voltage\n";
for (const auto& volt : voltages) {
cout << volt << "\n";
}
}
Instead of using many vectors you should use a data structure:
struct my_data {
double voltage;
double rpm;
double current;
double range;
}
And use a std::vector<my_data>.
Once you have that you should take a look at how to overload the input operator << for that data structure. But one thing at a time ;).
PS Don't use spaces so sparingly. Readability of code cannot be overestimated. And take a look at Why is “using namespace std;” considered bad practice?. Sooner or later it will create you problems.

Answer 2

You can create a vector of tuple to store the required data.
#include <iostream>
#include <vector>
#include <tuple>
using namespace std;
int main()
{ double voltage,rpm,current,range;
int total; //total set enter by user
cout << "Please enter how many sets of data you want to calculate:";
cin>>total;
cout<<"\n";
std::vector<std::tuple<double, double, double, double>> data;
for(int i=1;i<=total;i++)
{
cout<<"Enter he voltage "<<i<<":";
cin>>voltage;
cout<<"Enter the current "<<i<<":";
cin>>current;
cout<<"Enter the rpm "<<i<<":";
cin>>rpm;
cout<<endl;
double range= (voltage*1.2) + (current*0.5) + (rpm* 0.2);
data.emplace_back(std::make_tuple(current, current, rpm, range));
}
cout<<"Voltage\t\tCurrent\t\tRPM\t\tRange\n";
for(const auto& tup : data)
cout<<std::get<0>(tup)<<"\t\t"<<std::get<1>(tup)<<"\t\t"<<std::get<2>(tup)<<"\t\t"<<std::get<3>(tup)<<endl;
return 0;
}