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I am having a silly doubt in vector .In this following code
std::vector<char>ve(2); //creates a vector ve of size 2
std::vector<char>vechar[2]; //but what does it do ?
in ve vector I can write
ve[0]='a';
ve[1]='b';
but I cannot write
vechar[0]='a';
vechar[1]='b';
also I cannot do
std::cout << " vector -->>" << vechar[0];
It shows error.
505
Vector elements are indexed using the square bracket notation with a starting index of 0 just like arrays.
Coordinates and vectors In the Cartesian coordinate system, brackets are used to specify the coordinates of a point. For example, (2,3) denotes the point with x-coordinate 2 and y-coordinate 3. The inner product of two vectors is commonly written as. , but the notation (a, b) is also used.
Square brackets, often just called brackets in American English, are a set of punctuation marks that are most often used to alter or add information to quoted material.
A square bracket at one end of an interval indicates that the interval is closed at that end (i.e., the number adjacent to the opening or closing square bracket is included in the interval).
The std::vector<char>vechar[2] declares an array consisting of two vectors of char (it's the same syntax as used in, for example, int arr[2]).
Thus, vechar[0] is one vector of char, and vechar[1] is another vector of char.
Both vectors start off empty, but can be resized.
129
std::vector<char> v[10];
The above declaration creates an array of 10 empty vectors, same as int v[10];
29
Adding more to the answer of NPE .To add character 'a' to vechar[0] or vechar[1] we have to do the following things
vechar[0].resize(10);
vechar[1].resize(10);
vechar[0][0]='a'; //means vechar 0 0th element
vechar[0][1] = 'b'; //means vechar 0 1th element
vechar[1][0]='c';
vechar[1][1]='d';
std::cout<<vechar[0][0]<<vechar[0][1];
std::cout<<vechar[1][0]<<vechar[1][1];
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