从getline读取双打

Question

我想了解如何读取getline字符串并忽略使用bool函数的任何空格，换行符或制表符。然后，当输入为double或特定字符时，它们将仅调用函数，例如＆＃34; +， - ，*，/＆＃34;

#include<iostream>
//#include"inter.h"  // You may disregard any functions that would come from inter.h
#include<string>
using namespace std;

bool is_num(string input);
bool is_space(string input);
bool is_oper(string input);



int main(){

  string input;

  getline(cin,input);
  while (cin >> input); // read input until user enters ctrl d

  if(input.is_num(input == true) {
      // calls a push function from inter.h
      }
      else if(input.is_space == true){
      // ignores any white spaces, tabs or new line and continues to read input
      }
      else if (input.is_oper == true){
      //calls my pop function from inter.h
      }


}

bool is_num(string input){
// No idea what would go here
  return true;
}
bool is_space(string input){
// No idea what would go here needs to ignore any white space or endl;
  return true;
}
bool is_oper(string input){
// No idea what would go here
  return true;
}