Sort() sort function

1. Standard sort ： Yes int,double ,float And other data structure arrays

(1)#include<algorithm>

(2) grammar ：sort(a,a+n,cmp);

  explain ：

1）cmp To judge by , If you do not write, the default is ascending

2） Achieve descending order sort(a,a+n,greater<T>())//T According to the array a Type determines

Implementation of integer arrays a, In descending order ：sort(a,a+n,greater<int>())

//int a[n];n Represents a number , Is not a variable 
int a[10];
sort(a,a+10)

2. Custom sorting criteria —— make the best of cmp Determine whether the sorting function uses

The collection is written by bloggers , Don't write here .

Only on how to write according to custom guidelines cmp（） Understand and sort out ;

bool cmp(int x,int y)
{
return x>y;
}
//.....
int main()
{
//..
sort(a,a+n,cmp);
}

（1） Realization function ：int The type array is arranged from large to small

（2） understand ：（ Individual ）cmp() by bool Type function , Returned to sort() by bool value , Next ,x And y The order of corresponds to a The order in which values are taken for judgment , therefore x The relative position of should be in the front , If true No change ,false Just change it . So the implementation will make a The large element in the array is in the front , Small numbers come after .