Summary of some programming language aspects of the OJ exercise

1.STL Vector only four constructors

default(1)    ExplicitVector (Constallocator_type& Alloc =Allocator_type ()); Fill (2)    ExplicitVector (size_type N,Constvalue_type& val =value_type (),Constallocator_type& Alloc =Allocator_type ()); Range (3) Template<classInputiterator>Vector (inputiterator first, Inputiterator last,Constallocator_type& Alloc =Allocator_type ()); Copy (4) Vector (Constvector& x);

The first is the default constructor, and the parameter is the memory allocator.

The second is a fill type constructor with a Val value of n vector element type.

The third is the range's constructor, and the parameter is [First,last] left closed right open range.

The fourth one is the copy constructor, and the parameter is, of course, the const vector &.

The construction of a 2.STL two-dimensional array. such as vector<vector<int> > Vec;

There should be only the following methods:

Vector A1;a1.push_back (1); A1.push_back (2); A1.push_back (3 ); vector a2;a2.push_back (2); A2.push_back (3); A2.push_back (4  ); vec.push_back (A1); Vec.push_back (A2) ;

Therefore, initializing a two-dimensional array is cumbersome. It seems that there is no easier way to use a vector. At most, A1 and A2 are initialized with a range constructor, with parameters defined as array names and array names + lengths

Summary of some programming language aspects of the OJ exercise