convert string to number cpp code example

Example 1: string to int in c++

#include <iostream>
#include <string>
using namespace std;
int main() {
 
    string s = "10";
 
    try
    {
        int i = stoi(s);
        cout << i << '\n';
    }
    catch (invalid_argument const &e)
    {
        cout << "Bad input: std::invalid_argument thrown" << '\n';
    }
    catch (out_of_range const &e)
    {
        cout << "Integer overflow: std::out_of_range thrown" << '\n';
    }
 
    return 0;
}

Example 2: string to number in c++

// For C++11 and later versions
string str1 = "45"; 
string str2 = "3.14159"; 
string str3 = "31337 geek"; 

int myint1 = stoi(str1); 
int myint2 = stoi(str2); 
int myint3 = stoi(str3); 

// Output
stoi("45") is 45
stoi("3.14159") is 3
stoi("31337 geek") is 31337

Example 3: convert string to number c++

#include <iostream>
#include <sstream>
using namespace std;
int main()
{
	string str = "123456";
 	int n;
  	stringstream ( str ) >> n;
	cout << n; //Output:123456
	return 0;
}

Example 4: c++ string to int

// EXAMPLE
std::string sStringAsString = "789";
int iStringAsInt = atoi( sStringAsString.c_str() );

/* SYNTAX
atoi( <your-string>.c_str() )
*/

/* HEADERS
#include <cstring>
#include <string>
*/