convert a string to integer c++ code example

Example 1: convert stirng to int c++

int thing = std::stoi(string);

Example 2: string to int c++

#include <iostream>
#include <string>

int main() {

    std::string str = "123";
    int num;

    // using stoi() to store the value of str1 to x
    num = std::stoi(str);

    std::cout << num;

    return 0;
}

Example 3: 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 4: 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 5: c++ string to int

atoi( str.c_str() )

Example 6: string to int c++

// Both functions work identically though you'll need to use "#include <string>" 
atoi( str.c_str() );
stoi( str );