使用C ++引用类向量的元素

Question

I am trying to switch the elements of a class vector using pointers. I am not using this method simply to solve a small problem, but just to practice using this method for more difficult problems.

Here is my code

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

class thing{
    public:
        int index;
        int value;
        thing();
    private: int number;

};
thing::thing()
{
    number = 0;
}
void arrange(vector<thing>* array[]){
    for(int i=0; i<19; ++i){
        if(array[i]->value<array[i+1]->value){
            swap(array[i], array[i+1]);
            arrange(array);
        }
    }
}
int main(){
    vector<thing>** things = new thing*[20];
    for (int i=0; i < 20; ++i)
    {
        things[i] = new thing();  // default constructor
        things[i]->index = i;
        things[i]->value=rand() % 100;
    }
    cout << "The random array is: " << endl;
    for(int i=0;i<20;++i){
        cout << things[i]->value << endl;
    }
    arrange(*things);
    cout << "The arranged array is: " << endl;
    for (int i=0; i < 20; ++i)
    {
        cout << things[i]->value << endl;
    }
    return 0;

}

Answer 1

I think that is what you want:

#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

class thing{
    public:
    int index;
    int value;
    thing();
    private: int number;

};
thing::thing()
{
    number = 0;
}
// This arrange accept array of any length
void arrange(vector<thing *> &array)
{
    while(1)
    {
        int regressed=1;
        for(int i=0; i<array.size()-1; i++){
        if( (array[i]->value) < (array[i+1]->value) ){
            thing * tmp=array[i+1];
            array[i+1]=array[i];
            array[i]=tmp;
            regressed=0;
        }
        }
        if(regressed==1)
            return;
        }
}
int main(){
    vector<thing*> things; // init a container to contain " thing * " type vars
    for (int i=0; i < 20; ++i)
    {
    thing * t = new thing();  // default constructor
    t->index = i;
    t->value=rand() % 100;
    things.push_back(t);      // Add vars appended
    }
    cout << "The random array is: " << endl;
    for(int i=0;i<20;++i){
    cout << things[i]->value << endl;
    }
    arrange(things);
    cout << "The arranged array is: " << endl;
    for (int i=0; i < 20; ++i)
    {
    cout << things[i]->value << endl;
    }
    return 0;

}

The result output is :

The random array is: 
83
86
77
15
93
35
86
92
49
21
62
27
90
59
63
26
40
26
72
36
The arranged array is: 
93
92
90
86
86
83
77
72
63
62
59
49
40
36
35
27
26
26
21
15

Remember that:

vector<int> varname;
vector<int *> varname;

has the same logical meaning as:

int varname[size];
int* varname[size];

but vectors can be expanded automatically when you add new elements into it:

vectVar.push_back(sth);

Reading some docs about vector's usage first would be helpful enough.