Standard library type vector[c++ Primer]

Vector, which represents the container for the object, and all object types are the same.

Definition and initialization:

Vector<int> A; Default initialization, empty vector, no element

Vector<int> B (a); Equivalent to a copy of all elements in a in b=a;b

Vector<int> C (N, Val); Contains n repeating elements with a value of Val

Vector<int> c (n); Contains n elements, value is initialized by default

Vector<int> d{a,b,c,d..} The element that contains the number of initial values, each of which is given a corresponding value, equivalent to D={a,b,c,d ...}

Vector<string> v7{10}//There are 10 default initialized elements

If parentheses are used, the provided value is used to construct the vector object;

If you use curly braces, you want the list to be initialized

Add an element to a vector object: Take advantage of its member function push_back ()

1:

Vector<int> v;

for (int i=0; i!=100; ++i)

V.push_back (i);

2:

Vector<int> v;

int A;

while (Cin>>a)

V.push_back (a);

Access:

1: Range for statement

Vector<int> v{1,2,3,4,5};

for (auto &i:v)

I+=i;

2: Subscript operator

Vector<unsigned> scores (11,0);

unsigned grade;

while (Cin>>grade)

if (grade<=100)

++SCORES[GRADE/10];

Note: You cannot add an element with the subscript operator.

Standard library type vector[c++ Primer]