C++ 读取数学函数和排序

Question

我正在从格式为 f(x,y,f(x),g) 的文件中读取一个函数，一旦我读取了输入，它就被存储为一个 vector ，我试图获取逗号之间的每个值所以在这种情况下，我想将 x、y f(x) 和 g 作为单独的字符/字符串。我被卡住了，有什么想法吗？

Answer 1

这是我想出的解决方案:

#include <iostream>
#include <string>
#include <vector>
#include <sstream>

using namespace std;

//Split string into vector of strings
vector<string> split(string str, char delimiter) 
{
  vector<string> internal;
  stringstream ss(str); // Turn the string into a stream.
  string tok;

  while(getline(ss, tok, delimiter)) 
  {
    internal.push_back(tok);
  }

  return internal;
}

int main()
{
  string myInput = "f(x,y,f(x),g)";

  //Extract the string between outer brackets
  size_t startIndex = myInput.find_first_of("(") + 1;
  size_t endIndex   = myInput.find_last_of(")");
  string innerStr   = myInput.substr(startIndex, endIndex-startIndex);

  //Split the result by comma
  vector<string> sep = split(innerStr, ',');

  for(unsigned int i = 0; i < sep.size(); ++i)
  {
     cout << sep[i] << endl;
  }

}

希望对你有帮助