Trying to convert a string into a int using stringstream - c++

Question

I'm trying check if a string representation equals given integer. I'm meant to use stringstream for this in a function. I also have an operator= for this as well.
I'm a little confused on how to execute these together and if I'm missing something. This is the last bit to an assignment I have, this is just a small snippet of my whole program. I can't find many guides on this, and I sense they all direct me to atoi or atod, which I'm not allowed to use.
#ifndef INTEGER
#define INTEGER
using std::string;
class Integer
{
private:
int intOne;
string strOne;
public:
Integer() {
intOne = 0;
}
Integer(int y) {
intOne = y;
}
Integer(string x) {
strOne = x;
}
void equals(string a);
Integer &operator=(const string*);
string toString();
};
#endif
In this header I'm not sure what argument I'm to use for the = operator.
#include <iostream>
#include <sstream>
#include <string>
#include "Integer.h"
using namespace std;
Integer &Integer::operator=(const string*)
{
this->equals(strOne);
return *this;
}
void Integer::equals(string a)
{
strOne = a;
toString(strOne);
}
string Integer::toString()
{
stringstream ss;
ss << intOne;
return ss.str();
}
#include <iostream>
#include <cstdlib>
#include <conio.h>
#include <string>
#include <ostream>
using namespace std;
#include "Menu.h"
#include "Integer.h"
#include "Double.h"
int main()
{
Integer i1;
i1.equals("33");
cout << i1;
}
Sorry if its a bad question I'm not too familiar with this type of assignment and will take any help I can get. Thanks.

Answer 1

you can use std::to_strig() that lets you convert from int to a string that represents the same number.

Answer 2

So if i understand correctly, you want to overload operator =, and that is a bad idea, since operator= is used for assignment not for comparison.
The correct operator signature is:
ReturnType operator==(const TypeOne first, const TypeSecond second) [const] // if outside of class
ReturnType operator==(const TypeSecond second) [const] // if inside class
Since you can't compare string to integer (they are different types), you need to write your comparisment function, since you don't have one i will write one for you:
bool is_int_equal_string(std::string str, int i)
{
std::string tmp;
tmp << i;
return tmp.str() == i;
}
Last but not least, you need to merge both of those, into one convenient operator:
// inside your Integer class
bool operator==(std::string value) const
{
std::stringstream tmp;
tmp << intOne;
return tmp.str() == ref;
}
Now you can use this operator, just like any other:
Integer foo = 31;
if (foo == "31")
cout << "Is equal" << endl;
else
cout << "Is NOT equal" << endl;
I hope this helps.

Answer 3

If you are allowed to use std::to_string then it would be the best.
Otherwise, you could create a function to handle the equality between the string and the integer with the use of std::stringstream:
Example:
bool Integer::equal(const string& str)
{
stringstream ss(str);
int str_to_int = 0;
ss >> str_to_int;
if (intOne == str_to_int)
return true;
else
return false;
}
Combine this with an if statement:
int main()
{
Integer i{100};
if (i.equal("100"))
cout << "true" << endl;
else
cout << "false" << endl;
}