How to convert type string to char/double ?

in my program, i put the user enters into a string, then i need to get some information out of the string and store it into a char or double. would anyone give me some help ? THX :cool:

you need to specify what type of string you are using.

For "simple" null terminated char arrays use atoi()
if cString is a char[] and myInt is an int
myInt = atoi(cString);

For instances of the STL string class use the c_str() method in addition to atoi();

myInt = atoi(stlString.c_str());

Some other string classes have methods that facilitate the conversion

i used this:

Code:

---

#include<string>
string a;
double b;
char c;

---

how can i pass value in these variable ? :confused:

as he said up there by using c_str() function with the stl string class.

Code:

---

#include <iostream>
#include <stdlib.h>

using namespace std;

int main(int argc, char *argv[])
{
  string a;
  int b;
 
  a = "123456789";
 
  b = atoi(a.c_str());
 
  /* b now equals 123456789 */
 
  cout<<b;
 
  system("PAUSE");       
  return 0;
}

---

Since atoi only takes input of older character arrays for strings you have to use the function c_str() to convert a stl string to one. That code puts "123456789" into string a and then using atoi() puts it as a variable into int b.

And the C++ way...

Code:

---

#include <iostream>
#include <sstream>
#include <string>
using namespace std;

int main()
{
    string a = "123.456 Z";
    double d;
    char c;

    istringstream istream(a);

    istream >> d >> c;

    cout << "d = " << d << endl;
    cout << "c = " << c << endl;

    return 0;
}//main

---

gg

thank you for your help, now i have solved my problem. :D :D :D

And the FAQ says...
http://faq.cprogramming.com/cgi-bin/...&id=1043284385
http://faq.cprogramming.com/cgi-bin/...&id=1043284385