Vector Understanding a Wave ~ ~ ~

Vector;

Header file:

#include <vector>

Using NAMESPACESTD;

Defined:

vector< type >q;//similar to "type q[];"

vector< type >q[1010]//similar to "type q[1010][]"

Operation:

To deposit data into a vector:

Name of function: W. Push_back (data);

#include <iostream>

#include <vector>

using namespace Std;

vector<int>w;

int main ()

{

int x;

for (inti=0;i<7;i++)

{

scanf ("%d", &x);

W.push_back (x);//Plug the data into the end of the container. This container is very high-end, and you understand it as an array-like method of storage.

}

}

2. Let's get a better understanding of what's inside the vector;

Here are two functions: Q.begin (), Q.end ();

From the English name Begin,end very well understood must be the beginning and the end; = = nonsense.

Well, let's see what he is (data);

#include <stdio.h>

#include <iostream>

#include <vector>

Using NAMESPACESTD;

int main ()

{

vector<int>w;

for (int i=0;i<7;i++)//We'll plug in the I

{

W.push_back (i);

}

printf ("begin=%dend=%d\n", W.begin (), W.end ());

}

Results:

Very bad data--that's the memory. Then End-begin is 7. ~~~~~

We call W.begin (), W.end () as an iterator (t^t something very powerful) iterator is a so-called complex pointer "Here is not much to say what is an iterator, I do not know (ah, shame. "and what are the values that are stored separately?"

#include <stdio.h>

#include <iostream>

#include <vector>

Using NAMESPACESTD;

int main ()

{

vector<int>w;

for (int i=0;i<7;i++)//We'll plug in the I

{

W.push_back (i);

}

printf ("begin=%dend=%d\n", *w.begin (), *w.end ());

}

Results:

We understand very well that w.begin () "points" to the first value-0, but end , not 6? W.end () is the one at the end, equivalent to our definition array a[10], we are querying w.end (), which is equivalent to querying a[10] this element. So that means the last value, which is * (W.end ()-1);

#include <stdio.h>

#include <iostream>

#include <vector>

Using NAMESPACESTD;

int main ()

{

vector<int>w;

for (int i=0;i<7;i++)//We'll plug in the I

{

W.push_back (i);

}

printf ("begin=%d end=%d last is:%d\n", *w.begin (), *w.end (), * (W.end ()-1));

}

Results:

Then there is the traversal:

Here is a function w.size () that refers to the size of the range of values stored by this vector.

#include <stdio.h>

#include <iostream>

#include <vector>

Using NAMESPACESTD;

int main ()

{

vector<int>w;

for (int i=0;i<7;i++)//We'll plug in the I

{

W.push_back (i);

}

printf ("size=%d\n", W.size ());

}

Results:

Well, we can traverse it;

Here is a magical use of the same as the array!!! Why is it? T^t do not know AH;

#include <stdio.h>

#include <iostream>

#include <vector>

Using NAMESPACESTD;

int main ()

{

vector<int>w;

for (int i=0;i<7;i++)//We'll plug in the I

{

W.push_back (i);

}

for (int j=0;j<w.size (); j + +)

{

printf ("%d =%d\n", j+1,w[j]);

}

}

Results:

Another is that we know that W.begin (), W.end () is [iterator] (a complex "pointer"), then we use the same " iterator " to traverse, also can it;

Definition:vector<int>::iterator b;

#include <stdio.h>

#include <iostream>

#include <vector>

Using NAMESPACESTD;

int main ()

{

vector<int>w;

for (int i=0;i<7;i++)//We'll plug in the I

{

W.push_back (i);

}

Vector<int>::iterator b;

int cont=1;

For (B=w.begin (); B!=w.end (); b++)

{

printf ("%d =%d\n", cont++,*b);

}

}

Results:

There is also empty:

W.clear ();

#include <stdio.h>

#include <iostream>

#include <vector>

Using NAMESPACESTD;

int main ()

{

vector<int>w;

for (int i=0;i<7;i++)//We'll plug in the I

{

W.push_back (i);

}

Vector<int>::iterator A;

int cont=1;

For (A=w.begin (); A!=w.end (); a++)

{

printf ("%d =%d\n", cont++,*a);

}

W.clear ();

printf ("begin=%dend=%d\n", W.begin (), W.end ());

if (W.begin () ==w.end ())

printf ("Empty La la la!!! \ n ");

Vector<int>::iterator b;

Cont=1;

For (B=w.begin (); B!=w.end (); b++)

{

printf (" %d =%d\n", cont++,*b);

}

}

Results:

OK, there are a lot of other things to flip ah, very advanced stuff, try to know everything.

Vector Understanding a Wave ~ ~ ~