C++ how do i put a sting into a integer

[darknight909]

i have this string that has a number value and i want to put it into an integer so how would i go about this?

[Vinnie]

Maybe with a static class ?

static_cast<int>(variablename)

[Sieras]

Huh? There's and easier way though.. or just a simpler to understand:

integer = StrToInt(String);

for example:

int number;
String str;

.......

number = IntToStr(str);

.......

The same thing applies to double variables, but you have to use StrToFloat then

[darknight909]

error C3861: 'inttostr': identifier not found, even with argument-dependent lookup

ifstream myfile ("example.txt");
myfile.open ("example.txt");
getline (myfile,string);
int = inttostr(string);
myfile.close();

[Sieras]

You have to write IntToStr() with all the capital letters
And as I see from your '' error C3861: 'inttostr': '' , you just wrote inttostr
C++ doesn't have any formatting which would correct this on it's own.

[darknight909]

i fixed it to capital letters and I still get the same error

is there a header im missing?

or is there a way to use getline to grab an integer or a similar command

[Sieras]

Hm, strange.. I've always used that and it worked without any errors.
Oh well, try this then:

string s = "50";
int i = Int32.Parse(s);

or

string s = "50";
int i = Convert.ToInt32(s);

This should work.

[thecake90]

<
&gt:

[darknight909]

error C2228: left of '.Parse' must have class/struct/union type
type is ''unknown-type''

am I missing a header?

[Cornelius]

The C standard library already has a function built in:

#include <stdlib.h>
...
string s = "255";
int n = atoi( s.c_str() );

http://www.cppreference.com/stdstring/atoi.html

[darknight909]

hmm well that seems to work but for some reason now
#include <iostream>
#include <string>
#include <sstream>
#include <fstream>
#include <stdlib.h>
#include <stdio.h>

using namespace std;

int x;
int y;
string a;

int main() {
x = 2;
a = x;
cin >> y;
if (y == 1) {
ofstream myfile;
myfile.open ("example.txt");
myfile << a;
myfile.close();
return 0;
}else if(y == 2) {
ifstream myfile ("example.txt");
myfile.open ("example.txt");
getline (myfile,a);
x = atoi(a.c_str());
myfile.close();
cout << x;

return 0;
}

x doesnt output anything