The code inputs an int, n, which is the number of lines to follow. Then, on each line, the first number goes to array A, the second to B, and the third to C. I then pass these 4 arguments to sub which I have no control over (in an object file where I don't know the implementation). All I know is that it returns an int.
What I do then is write n, the three arrays, and the result of sub into an output file. Pretty simple code.
This code works as expected, but I just want to see if there are any conventions I should be following (especially C++11) and ideas to consider for efficiency.
#include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <sstream>
#include "sub.h"
int main()
{
std::ifstream file;
file.open(...);
if (!file) {
std::cerr << "Error opening file." << std::endl;
return EXIT_FAILURE;
}
int n;
std::string firstLine;
getline(file, firstLine);
std::stringstream(firstLine) >> n;
int a,b,c;
std::vector<int> A1,B1,C1;
while (file >> a >> b >> c) {
A1.push_back(a);
B1.push_back(b);
C1.push_back(c);
}
file.close();
std::ofstream output;
output.open(...);
output << n << "\n";
size_t size = A1.size();
for (size_t i=0; i<size; ++i) {
output << A1[i] << " " << B1[i] << " " << C1[i] << std::endl;
}
//call sub method with pointer to beginning of vectors
//I have no control over sub method, its signature is (int, int*, int*, int*)
int n1 = sub(n, &A1[0], &B1[0], &C1[0]);
//output result and close file
output << n1;
output.close();
}
Example input:
0 1 2 <- This is A[0], B[0], C[0]
2 3 4 <- This is A[1], B[1], C[1]
4 5 6 <- This is A[2], B[2], C[2]
The range-based for-loop would not work in this case. It would, however, if I printed all of A, B, or C on one line.
