Thread: I can't understand the behavior of my vector in this recursion function

Hi I have a class where I define a

Code:

 vector<char *> myVector

to be a private variable.

This variable will store permutations of a string

For example, if the string is "123" it will store "123","213","321" etc

I then define a function that does the permutations, the function is the following:

Code:

void PermClass::findPerms(char *set, int begin, int end){

	int i;
	int range = end - begin;
	if(range == 0) myVector.push_back(set);//(1)
	else{

		for(i=0;i<range;i++){
			swap(set[begin],set[begin+i]);
			findPerms(set,begin+1,end);
			swap(set[begin],set[begin+i]);
		}
	}
}

I have tried some debugging and realized that the variable "set" has the next permutation at position (1).

However, when the recursion ends, when I output the values of the vector by using an iterator like this:

Code:

void PermClass::showVector(){

	int i;
	vector<char *>::iterator it;
	for(it = myVector.begin(); it!=myVector.end(); it++){
		cout<<*it<<endl;
	}
	cin.get();

}

I get as an output

Code:

123
123
123
123
123
123

can someone explain me what's wrong? thanks in advance

Originally Posted by laserlight

It looks like you are just storing pointers to the same string. Maybe you should use a vector<string> instead.

thanks a lot