Answers for "c++ string to number"

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

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;
}

string to int c++

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

c++ string to int

atoi( str.c_str() )

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>
*/

how to convert string to int in c++

string s = "123";
int n = s.size();
int num = 0;
 for(int i = 0 ; i<n;i++)//this what stoi built function do XD
 {
  num = num*10+(s[i]-'0');
 }