如何将函数的返回结果添加到也在用 C++ 编写的文件中？

Question

你好，我目前正在编写一个程序来读取文本文件中的数据，执行计算，然后将结果输出到输出文本文件

这是完整的程序

主文件

int main() {

readFile(inputFile1, inputFile2, inputFile3, lines);
robotComplexity(lines);
robotVariability(lines);
writeFile(outputFile, lines, robotComplexity(lines), robotVariability(lines));

getch();
return 0;

}

void Customer() {
std::string customerName;
std::string projectName;
std::string partNumber;;
}

void Parts() {

char partCode;
std::string partName;
int maximum;
int minimum;
int complexity;

}
void Builder() {

std:string name;
int ability;
int variability;

}

实施文件

std::vector<std::string> lines;
std::string inputFile1 = "Builders.txt";
std::string inputFile2 = "Parts.txt";
std::string inputFile3 = "Customers.txt";
std::string outputFile = "output.txt";
std::string input;

void readFile(std::string const& inputFile1, std::string const& inputFile2, std::string const& inputFile3,
              std::vector<std::string>& lines) //function to read Builders, Customers and Parts text file
{
   std::ifstream file1(inputFile1);
   std::ifstream file2(inputFile2);
   std::ifstream file3(inputFile3);
   std::string line;

   while(std::getline(file1, line)) 
   {
      lines.push_back(line);
   }

     while(std::getline(file2, line)) 
   {
      lines.push_back(line);
   }

     while(std::getline(file3, line)) 
   {
      lines.push_back(line);
   }

}


double robotComplexity(std::vector<std::string>& lines) { //takes in the out.txt file

std::string output = lines[0]; //so far only reads the first line of the output file. 
std::string input = output.substr(18,1);

double complexity = 20 * atoi(input.c_str());


   if(complexity > 100) {
      complexity = 100;
   }

cout << "The Robot Complexity is: " << complexity << endl;
return complexity;
}

double robotVariability(std::vector<std::string>& lines) {

std::string output = lines[0]; //so far only reads the first line of the output file. 
std::string input = output.substr(15,2);

double variability;

variability = 5 + atoi(input.c_str());

cout << "The Robot Variability is: " << variability << endl;
return variability;

}

void writeFile(std::string const& outputFile,
               std::vector<std::string> const& lines, double unitComplexity, double unitVariability) //writes to a file output.txt the end calculations. 
{
   std::ofstream file(outputFile);
   for(std::string const& line: lines)
   {
      file << line << std::endl;
   }

   for(double x: unitComplexity) {
      file << x << std::endl;
   }


}

我也想提请注意的代码是实现文件中的最后3个函数，分别是robotCompelxity、robotVariability和writeFile。前 2 个函数 pefrom 计算基于读取的文件和 writeFile，到这个时间点，包含主文件中看到的每个机器人的详细信息（IE、构建器、客户和零件）这个工作和详细信息输出成功到文件。

我的问题在于 robotVariability 和 robotComplexity 函数。正如在 writeFile 函数参数中看到的，in 接收一个作为输出文件的字符串 const，一个作为机器人详细信息的向量列表，以及两个双精度数，作为 robotVariability 和 robotComplexity 函数的结果。我试图创建一个增强的 for 循环以将此类结果添加到输出文件中，如最后这行代码所示

for(double x: unitComplexity) {
      file << x << std::endl;
   }

但是，这会导致读取 "this range-based 'for' statement requires a suitable "begin" function and none was found" 表示的错误。我不确定如何解决这个问题。

重申一下，我只是尝试将 robotComplexity 和 robotVariability 都是双精度类型的结果添加到 writeFile 函数中正在写入的文件中。谢谢你。

Answer 1

更改您的代码以输出没有像这样的范围 for 循环的双打

void writeFile(std::string const& outputFile,
               std::vector<std::string> const& lines, double unitComplexity, double unitVariability) //writes to a file output.txt the end calculations. 
{
   std::ofstream file(outputFile);
   for(std::string const& line: lines)
   {
      file << line << std::endl;
   }

   file << unitComplexity << std::endl;
   file << unitVariability << std::endl;
}

并且该函数会将双打写入文本文件。范围 for 循环仅适用于向量和数组等对象，而不适用于单值变量。

如何将函数的返回结果添加到也在用 C++ 编写的文件中？

How to add the returned result of a function to a file being written too in C++?

c++

ofstream