How to print a variable using string using C++

Question

Suppose my code is:

int x = 4;
string alpha;

Now i want to print x using alpha, that is using

cout << alpha;

For example in this case i want 4 to be printed on screen, how to do this ?

c++ prior to c++11 still works in c++11, generally speaking! — Joe, Apr 11 '14 at 14:23
C++ zealots will disapprove, but you can still do it the C way: `printf("%d", x);` (albeit directly to screen, bypassing the `alpha` and `cout` completely) — Agent_L, Apr 11 '14 at 14:27
@Bathsheba: I don't think we need a new question to hang C++11 answers on. The one linked as a dupe has C++11 answers, including the top voted and accepted answer. There are probably at least dozens of other duplicates too. — Fred Larson, Apr 11 '14 at 14:49

score 3 · Accepted Answer · answered Apr 11 '14 at 14:23

3

If you have C++11, you can use std::to_string(x).

Pre C++11 it was a little more difficult. You could use std::stringstream:

std::stringstream ss;
ss << 4;
std::string alpha = ss.str();

answered Apr 11 '14 at 14:23

Bathsheba

Lee White · Answer 2 · 2014-04-11T14:28:51.623

1

int x = 4;
string alpha = to_string(x);
cout << alpha;

To answer the question in your comment: you can turn multiple numbers into one string by concatenating their string values:

alpha = to_string(x1) + to_string(x2)

Or with a space in between:

alpha = to_string(x1) + " " + to_string(x2)

edited Apr 11 '14 at 14:28

answered Apr 11 '14 at 14:23

Lee White

What about if i want to print two integers simultaneously using 1 string ? – Nishu Apr 11 '14 at 14:25
2

`alpha = to_string(x) + " " + to_string(y)`? – Apr 11 '14 at 14:26

score 1 · Answer 3 · answered Apr 11 '14 at 14:32

A good way is to create your own function so then you can reuse it everywhere.

std::string toString (int a)
{
  std::stringstream mynewstream;
  mynewstream << a;
  return mynewstream.str();
}

Then if you want to do concatenate some it's easy:

cout << "This subject has been posted already" << toString(4000) << " times.";

or

int a = 1;
int b = 2;

string concat = toString(a) + toString(b);
cout << concat;

Will output: "12"

3 Answers3