Why c++ does not support multiple initializers in for loop? [duplicate]

Question

Possible Duplicate:
In C++ why can't I write a for() loop like this: for( int i = 1, double i2 = 0;
Why is it so 'hard' to write a for-loop in C++ with 2 loop variables?

#include <iostream>
using namespace std;

int main()
{
    for (int i = 0, double j = 3.0; i < 10; i++, j+=0.1)
        cout << i << j << endl;
    return 0;
}

does not compile, becuase there are two declaration in the for-loop initializer block.

But Why?

Answer 1

If you want int and double both, in the initialization, then one way to do this is to define an anonymous struct! Yes, you can define struct in the for loop, as well. It seems to be a less known feature of C++:

#include <iostream>

int main()
{
    for( struct {int i; double j;} v = {0, 3.0}; v.i < 10; v.i++, v.j+=0.1)
       std::cout << v.i << "," << v.j << std::endl; 
}

Output:

0,3
1,3.1
2,3.2
3,3.3
4,3.4
5,3.5
6,3.6
7,3.7
8,3.8
9,3.9

Online demo : http://ideone.com/6hvmq