How to Convert string to Number

String streams are of great help for conversion between strings and numbers. The folowing code snippet converts string to int.

string MyString("123");
stringstream SStream(MyString);
int Num = 0;
SStream >> Num;

The resulting Num contains the value 123.

It can be extended for any number type (float, double etc.) So the conversion function can be enhanced as a template as given below.

#include <iostream>
#include <sstream>
using namespace std;
template<typename T>

T Convert(const string& MyString)
{
   stringstream SStream(MyString);
   T Num = 0;
   SStream >> Num;
   return Num;
}

int main()
{
   string Str("123.45");
   float fNum = Convert<float>(Str);
   Str = "24";
   int iNo = Convert<int>(Str);
   return 0;
}

Click here to see how to convert a number to string

Click here to see how to convert CString to std::string