有懂C++的吗，这段代码啥意思？

Question

#include <fstream>

#include <iostream>

#include <string>

#include <tuple>

#include <vector>

using std::cout;

using std::endl;

using std::ios;

using std::ifstream;

using std::ofstream;

using std::make_tuple;

using std::string;

using std::tuple;

using std::vector;

int main() {

 vector<tuple<time_t, string>> ps = vector<tuple<time_t, string>> {

 make_tuple(1539096140, "C:MyPhotosphoto1.jpg"),

 make_tuple(1539096146, "C:MyPhotosphoto5.jpg"),

 make_tuple(1539096143, "C:MyPhotosphoto2.jpg"),

 make_tuple(1539096150, "C:MyPhotosphoto3.jpg"),

 make_tuple(1539096145, "C:MyPhotosphoto4.jpg"),

 };

 cout << endl;

 cout << "-----------------------------" << endl;

 cout << "Photo list (timestamp | path)" << endl;

 cout << "-----------------------------" << endl;

 cout << std::get<0>(ps.at(0)) << " | " << std::get<1>(ps.at(0)) << endl;

 cout << std::get<0>(ps.at(1)) << " | " << std::get<1>(ps.at(1)) << endl;

 cout << std::get<0>(ps.at(2)) << " | " << std::get<1>(ps.at(2)) << endl;

 cout << std::get<0>(ps.at(3)) << " | " << std::get<1>(ps.at(3)) << endl;

 cout << std::get<0>(ps.at(4)) << " | " << std::get<1>(ps.at(4)) << endl;

 cout << endl;

 ifstream infile("../../resources/flight-data2.bin", ios::binary);

 time_t t1;

 time_t t2;

 time_t t3;

 time_t t4;

 time_t t5;

 double la1;

 double la2;

 double la3;

 double la4;

 double la5;

 double lo1;

 double lo2;

 double lo3;

 double lo4;

 double lo5;

 double a1;

 double a2;

 double a3;

 double a4;

 double a5;

 infile.read(reinterpret_cast<char*>(&t1), sizeof(time_t));

 infile.read(reinterpret_cast<char*>(&la1), sizeof(double));

 infile.read(reinterpret_cast<char*>(&lo1), sizeof(double));

 infile.read(reinterpret_cast<char*>(&a1), sizeof(double));

 infile.read(reinterpret_cast<char*>(&t2), sizeof(time_t));

 infile.read(reinterpret_cast<char*>(&la2), sizeof(double));

 infile.read(reinterpret_cast<char*>(&lo2), sizeof(double));

 infile.read(reinterpret_cast<char*>(&a2), sizeof(double));

 infile.read(reinterpret_cast<char*>(&t3), sizeof(time_t));

 infile.read(reinterpret_cast<char*>(&la3), sizeof(double));

 infile.read(reinterpret_cast<char*>(&lo3), sizeof(double));

 infile.read(reinterpret_cast<char*>(&a3), sizeof(double));

 infile.read(reinterpret_cast<char*>(&t4), sizeof(time_t));

 infile.read(reinterpret_cast<char*>(&la4), sizeof(double));

 infile.read(reinterpret_cast<char*>(&lo4), sizeof(double));

 infile.read(reinterpret_cast<char*>(&a4), sizeof(double));

 infile.read(reinterpret_cast<char*>(&t5), sizeof(time_t));

 infile.read(reinterpret_cast<char*>(&la5), sizeof(double));

 infile.read(reinterpret_cast<char*>(&lo5), sizeof(double));

 infile.read(reinterpret_cast<char*>(&a5), sizeof(double));

 infile.close();

 cout << "---------------------------------------------------------" << endl;

 cout << "Flight data (timestamp | latitude | longitude | altitude)" << endl;

 cout << "---------------------------------------------------------" << endl;

 cout << t1 << " | " << la1 << " | " << lo1 << " | " << a1 << endl;

 cout << t2 << " | " << la2 << " | " << lo2 << " | " << a2 << endl;

 cout << t3 << " | " << la3 << " | " << lo3 << " | " << a3 << endl;

 cout << t4 << " | " << la4 << " | " << lo4 << " | " << a4 << endl;

 cout << t5 << " | " << la5 << " | " << lo5 << " | " << a5 << endl;

 cout << endl;

 cout << "--------------------------------" << endl;

 cout << "Matching photos with coordinates" << endl;

 cout << "--------------------------------" << endl;

 tuple<string, double, double, double> matched1;

 tuple<string, double, double, double> matched2;

 tuple<string, double, double, double> matched3;

 tuple<string, double, double, double> matched4;

 tuple<string, double, double, double> matched5;

 if (t1 == std::get<0>(ps.at(0))) {

 matched1 = make_tuple(std::get<1>(ps.at(0)), la1, lo1, a1);

 }

 if (t1 == std::get<0>(ps.at(1))) {

 matched1 = make_tuple(std::get<1>(ps.at(1)), la1, lo1, a1);

 }

 if (t1 == std::get<0>(ps.at(2))) {

 matched1 = make_tuple(std::get<1>(ps.at(2)), la1, lo1, a1);

 }

 if (t1 == std::get<0>(ps.at(3))) {

 matched1 = make_tuple(std::get<1>(ps.at(3)), la1, lo1, a1);

 }

 if (t1 == std::get<0>(ps.at(4))) {

 matched1 = make_tuple(std::get<1>(ps.at(4)), la1, lo1, a1);

 }

 if (t2 == std::get<0>(ps.at(0))) {

 matched2 = make_tuple(std::get<1>(ps.at(0)), la2, lo2, a2);

 }

 if (t2 == std::get<0>(ps.at(1))) {

 matched2 = make_tuple(std::get<1>(ps.at(1)), la2, lo2, a2);

 }

 if (t2 == std::get<0>(ps.at(2))) {

 matched2 = make_tuple(std::get<1>(ps.at(2)), la2, lo2, a2);

 }

 if (t2 == std::get<0>(ps.at(3))) {

 matched2 = make_tuple(std::get<1>(ps.at(3)), la2, lo2, a2);

 }

 if (t2 == std::get<0>(ps.at(4))) {

 matched2 = make_tuple(std::get<1>(ps.at(4)), la2, lo2, a2);

 }

 if (t3 == std::get<0>(ps.at(0))) {

 matched3 = make_tuple(std::get<1>(ps.at(0)), la3, lo3, a3);

 }

 if (t3 == std::get<0>(ps.at(1))) {

 matched3 = make_tuple(std::get<1>(ps.at(1)), la3, lo3, a3);

 }

 if (t3 == std::get<0>(ps.at(2))) {

 matched3 = make_tuple(std::get<1>(ps.at(2)), la3, lo3, a3);

 }

 if (t3 == std::get<0>(ps.at(3))) {

 matched3 = make_tuple(std::get<1>(ps.at(3)), la3, lo3, a3);

 }

 if (t3 == std::get<0>(ps.at(4))) {

 matched3 = make_tuple(std::get<1>(ps.at(4)), la3, lo3, a3);

 }

 if (t4 == std::get<0>(ps.at(0))) {

 matched4 = make_tuple(std::get<1>(ps.at(0)), la4, lo4, a4);

 }

 if (t4 == std::get<0>(ps.at(1))) {

 matched4 = make_tuple(std::get<1>(ps.at(1)), la4, lo4, a4);

 }

 if (t4 == std::get<0>(ps.at(2))) {

 matched4 = make_tuple(std::get<1>(ps.at(2)), la4, lo4, a4);

 }

 if (t4 == std::get<0>(ps.at(3))) {

 matched4 = make_tuple(std::get<1>(ps.at(3)), la4, lo4, a4);

 }

 if (t4 == std::get<0>(ps.at(4))) {

 matched4 = make_tuple(std::get<1>(ps.at(4)), la4, lo4, a4);

 }

 if (t5 == std::get<0>(ps.at(0))) {

 matched5 = make_tuple(std::get<1>(ps.at(0)), la5, lo5, a5);

 }

 if (t5 == std::get<0>(ps.at(1))) {

 matched5 = make_tuple(std::get<1>(ps.at(1)), la5, lo5, a5);

 }

 if (t5 == std::get<0>(ps.at(2))) {

 matched5 = make_tuple(std::get<1>(ps.at(2)), la5, lo5, a5);

 }

 if (t5 == std::get<0>(ps.at(3))) {

 matched5 = make_tuple(std::get<1>(ps.at(3)), la5, lo5, a5);

 }

 if (t5 == std::get<0>(ps.at(4))) {

 matched5 = make_tuple(std::get<1>(ps.at(4)), la5, lo5, a5);

 }

 cout << "Matching done!" << endl;

 cout << endl;

 cout << "--------------------------------------" << endl;

 cout << "Writing GPS coordinates to image files" << endl;

 cout << "--------------------------------------" << endl;

 cout << "Writing (latitude " << std::get<2>(matched1) << ", longitude " << std::get<1>(matched1) << ", altitude " << std::get<3>(matched1) << ") to "" << std::get<0>(matched1) << """ <<  endl;

 cout << "Writing (latitude " << std::get<2>(matched2) << ", longitude " << std::get<1>(matched2) << ", altitude " << std::get<3>(matched2) << ") to "" << std::get<0>(matched2) << """ << endl;

 cout << "Writing (latitude " << std::get<2>(matched3) << ", longitude " << std::get<1>(matched3) << ", altitude " << std::get<3>(matched3) << ") to "" << std::get<0>(matched3) << """ << endl;

 cout << "Writing (latitude " << std::get<2>(matched4) << ", longitude " << std::get<1>(matched4) << ", altitude " << std::get<3>(matched4) << ") to "" << std::get<0>(matched4) << """ << endl;

 cout << "Writing (latitude " << std::get<2>(matched5) << ", longitude " << std::get<1>(matched5) << ", altitude " << std::get<3>(matched5) << ") to "" << std::get<0>(matched5) << """ << endl;

 cout << endl;

 return 0;

}

Answer 1

基本就是std::vector std::tuple的使用练习。
vector，tuple是stl中的模板容器，就是可以存放各种类型数据的容器（可理解为集合）。
按照这些关键字上网搜索你可以学到更多。
如果只依赖别人说的不自己去查，你所得有限或者一无所得。