C ++ standard library functions of the sort function for sorting

Sorting and searching can be said is the most classic problem of the computer field,
and the C ++ standard library header files ** algorithm ** has been built based on the function sort quick sort, simply calling this function, you can easily complete the sort.

Sort functions are briefly described below: sort (first, last, comp) function takes three parameters:

The starting address to be sorted sequence: 1. first
end address to be sorted sequence (start address of the last element): 2. Last
3. CoMP: ordering, may not be filled, while ascending order by default does not fill

Example 1: Default ascending sort

#include <iostream>
#include <algorithm>

using namespace std;

int main ()
{
    int arr[5] = {3, 6, 1, 4, 7}; 
    cout << "排序前:";
    for (int i = 0; i < 5; i++) {
        cout << arr[i] << ' ';
    }
    cout << endl;
    Sort (ARR, ARR + . 5 );                 // Sort: Ascending default 
    COUT << " sorted: " ;
     for ( int I = 0 ; I < . 5 ; I ++ ) {
        cout << arr[i] << ' ';
    }
    return 0; 
}

 

Output:
Before sorting: . 3  . 6  . 1  . 4  . 7 
sorted: . 1  . 3  . 4  . 6  . 7

 

Example 2: in descending order, you have written a Sort

#include <iostream>
#include <algorithm>

using namespace std;

BOOL the Compare ( int X, int Y)                 // Sort Descending 
{
     return X> Y;
}

int main ()
{
    int arr[5] = {3, 6, 1, 4, 7}; 
    cout << "排序前:";
    for (int i = 0; i < 5; i++) {
        cout << arr[i] << ' ';
    }
    cout << endl;
    Sort (ARR, ARR + . 5 , the Compare);         // Sort: using a descending sort mode 
    COUT << " after sorting: " ;
     for ( int I = 0 ; I < . 5 ; I ++ ) {
        cout << arr[i] << ' ';
    }
    return 0; 
}

 

Output:
: Before sorting . 3  . 6  . 1  . 4  . 7 
sorted: . 7  . 6  . 4  . 3  . 1

 

Example 3: Sort by its own definition, can achieve many scenes sort of
example: sort of student achievement, sorted by highest to lowest, and student information printing. Information including school students, grades; if student achievement are the same, according to the size of the student number in ascending order.

#include <iostream>
#include <algorithm>

using namespace std;

struct Student {
     int Number;             // Student ID 
    int Score;              // score 
};

const  int MAXN = 100 ;

Student arr[MAXN];

BOOL the Compare (Student X, Y Student) {
     IF (x.score == y.score) {             // the same results, a small number of learning front 
        return x.number < y.number;
    } 
    the else {
         return x.score> y.score;         // a high score former 
    }
} 

int main ()
{
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> arr[i].number >> arr[i].score;
    }
    sort(arr, arr + n, Compare);
    cout << endl;
    for (int i = 0; i < n; i++) {
        cout << arr[i].number << ' ' << arr[i].score << endl;
    }
    return 0;
}

 

Test:
 . 4 
. 1  98 
2  90 
. 3  98 
. 4  89

1 98
3 98
2 90
4 89