Thread: Get Variable Contents

Thanks for the information...I just figured out how to accomplish what I was trying to do without a "variable variable". For those who are asking the same question, this is what I did:

Code:

const char* var1 = "test";
const char* var2 = "";
const char* var3[] = {var1, var2};
int a = 2;
int c = 0;

for(int b=0; b<a; b++) {
     if(var3[b]!="") {
          var3[c] = var3[b];
          c++;
     }
}

while(c<a) {
     var3[c] = "";
     c++;
}

That's basically all I needed (to remove variables that were blank).

EDIT: This is not a very good example because var3 at the end will equal var3 at the beginning, but this code works for what I was trying to accomplish.

EDIT EDIT: What the above code does is moves the blank entries to the end of the array.

Originally Posted by The Wazaa

An easier way is to use pointers, which you almost did. Pointers is a kind of variable variable if you would write:

...

Code:

const char* variable2;
const char* variable1 = variable2;
strcpy(variable2, "test");

std::cout << variable1;

it would output the contents of variable2. Notice that you got to declare variable2 before pointing to it, or you won't be able to compile.

...

No, variable2 is an uninitialized pointer. You can't just copy data to it (safely) without first allocating space for it to point to.

Oh, I thought that strcpy() did that for you. At least I know that it can extend the allocated space, but when you say it I'm not sure that it allocates new space for you. *Testing* Oh, didn't work. Sorry about that.

EDIT: fixed it :

Code:

char* variable2 = new char;
char* variable1 = variable2;
strcpy(variable2, "test");

std::cout << variable1;

Originally Posted by The Wazaa

Oh, I thought that strcpy() did that for you. At least I know that it can extend the allocated space, but when you say it I'm not sure that it allocates new space for you. *Testing* Oh, didn't work. Sorry about that.

EDIT: fixed it :

Code:

char* variable2 = new char;
char* variable1 = variable2;
strcpy(variable2, "test");

std::cout << variable1;

You expect to copy 5 bytes into a pointer that only points to a buffer of a single byte?

> const char* variable1 = "variable2";
> const char* variable2 = "test";
> std::cout << variable1;

Maybe something like

Code:

std::map<std::string, std::string> table;
table["myvariable"] = "test";

Then later on, you can do

Code:

cout << table["myvariable"];

no strcpy will never ever touch the memory.

It works because you were lucky. This program crashes for me for example:

Code:

#include <iostream>
using namespace std;


int main() 
{
	char foo[] = "abc";	// size = 4 bytes.
	cout << "foo: " << foo << endl;
	strcpy(foo, "abcdefgh");
	cout << "foo: " << foo << endl;
}