I want to calculate total and average of data from text file using C++ -

i want calculate total , average of data text file using c++.
here code , text file. code not showing on run

#include <iostream> #include <fstream> #include <sstream> #include <iomanip>  using namespace std;  string double2string(double); double string2double(string);  int main(int argc, char* argv[]){  fstream dfile;    string s1; string amount; double damount; double sum = 0;   dfile.open(argv[1]);       dfile >> amount;      damount = string2double(amount);      while(damount){      sum = sum + damount;  }  string total = double2string(sum);   dfile.clear();  dfile.close();  cout << total;   return 0; } 

functions convert string double , double string

string double2string(double d){ ostringstream outstr;  outstr << setprecision(2) << fixed << setw(10) << d;  return outstr.str();  };  double string2double(string s1){  istringstream instr(s1);  double n;  instr >> n;  return n;  } 

here text file "data.txt"

  234   456   789 

you need use while loop. you're reading in 1 line, need make sure keep reading in lines until end of file.

also, might want use standard library function: std::stoi c++11 , onward version works std::string, std::atoi <cstdlib> works std::string.c_str().

#include <iostream> #include <fstream> #include <string>  //compile c++11; -std=c++11 int main(int argc, char** argv) {     std::fstream file;      //open file     file.open(argv[1]);     std::string buffer = "";     int sum = 0;     int n = 0;      //check file validity, , keep reading in line line.     if (file.good()) {         while (file >> buffer) {             n = std::stoi(buffer);             sum += n;         }          std::cout << "sum: " << sum << std::endl;     } else {         std::cout << "file: " << argv[1] << "is not valid." << std::endl;     }      return 0; }