sort () function uses detailed

Need to import header file using <algorithm>

#include<algorithm>

Syntax Description: sort (begin, end, cmp), cmp argument can not, if there is no default non-descending order.

I. The basic data type int sort used Case

#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
int main()
{
    int a[5]={1,3,4,2,5};
    sort(a,a+5);
    for(int i=0;i<5;i++)
            cout<<a[i]<<' ';
    return 0;
 }

Because there is no cmp parameter, the default non-descending order, the result is:

1 2 3 4 5

If the design is non-ascending order, then the function cmp prepared:

bool cmp（int a,int b）

{

　　return a>b;

}

In fact, for such a simple task (type support "<", ">" comparison operators, etc.), absolutely no need to write out a class. Standard Library has a ready-made, in functional inside, include came on the line. functional provides a bunch of template-based comparison function object. They are (see the name to know the meaning): equal_to <Type>, not_equal_to <Type>, greater <Type>, greater_equal <Type>, less <Type>, less_equal <Type>. For this problem is, greater and less sufficient, to take over the direct use:

升序：sort(begin,end,less<data-type>());

降序：sort(begin,end,greater<data-type>()).

int  main ( )
{
      int a[20]={2,4,1,23,5,76,0,43,24,65},i;
      for(i=0;i<20;i++)
          cout<<a[i]<<endl;
      sort(a,a+20,greater<int>());
      for(i=0;i<20;i++)
          cout<<a[i]<<endl;
      return 0;
}

II. Reference data type of string

Among a string of characters Sort:

Can be accomplished using an iterator sequential ordering

#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
int main()
{
    string str("hello world");
    sort(str.begin(),str.end());
    cout<<str;
    return 0;
 }

Results: Space dehllloorw

Use a reverse iterator can complete the reverse order

#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
int main()
{
    string str("hello world");
    sort(str.rbegin(),str.rend());
    cout<<str;
    return 0;
 }

The results: wroolllhde space

Comparison between the sort of string

#include<iostream>
#include<cstring >
#include<algorithm>
using namespace std;
int main()
{
    string a[4];
    for(int i=0;i<4;i++)
        getline(cin,a[i]);
    sort(a,a+4);
    for(int i=0;i<4;i++)
        cout<<a[i]<<endl;
    return 0;
}

III. In an example of the structure of the two sorting

#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
struct link
{
    int a,b;
};
bool cmp(link x,link y)
{
    if(x.a==y.a)
        return x.b>y.b;
    return x.a>y.a;
}
int main()
{
    link x[4];
    for(int i=0;i<4;i++)
        cin>>x[i].a>>x[i].b;
    sort(x,x+4,cmp);
    for(int i=0;i<4;i++)
        cout<<x[i].a<<' '<<x[i].b<<endl;
    return 0;
 }