push_back

[vastrolorde]

Could someone explain me what does this funcion do. English isnt my native tongue, so it causes me some problems.

If this doesent do it, then what function add a character ata the begginning of string. So that character that once was on the position of 0 is now 1, and what was 1 is now 2 etc.

[Kazekan]

push_back() adds whatever data is within the parenthesis to the end of the vector, thereby increasing the size of the vector by 1. For example:

vector <int> test;
int myNumber;

cin >> myNumber;
test.push_back(myNumber);

would result in a vector that has one value - that value being whatever you set myNumber to be. Let's assume you entered 1. Your vector would now look like: {1}

If you asked for a different number and pushed that value back (let's say you entered 2), your vector would look like: {1,2}

If you want to put something at the beginning, check out:

http://www.cplusplus.com/reference/stl/vector/insert/

[Shinigami]

You can try a deque container http://www.cplusplus.com/reference/stl/deque/
it has methods push_back() and push_front(), and new value at the end and at the beginning of sequence.

[TheBeardedQuack]

Failing any of these you could do it the long way round by adding a value using push_back() and have a temparary variable and a for statement to move everything down by one field...
And if you want to asign anything to the first character its just vectorName[0] = assignment

[Kazekan]

The insert member function basically does all of the work that SatsumaBenji is describing, but automatically. Either way, it's definitely more taxing on the system as opposed to just putting a value in the back, but there are definitely reasons to want a value in the front. Doing it the manual way would be good practice though if you're a beginner.

Depending on what you're doing though, you could always just read the vector backwards, if all you're worried about is output. :)

[vastrolorde]

so i need to create a vector. THen eachtim i want to add something to beginngin i use vector.insert(it, value). Can the value be int type, ot does it have to be char or string or whatever.

[MrHutch]

Can the value be int type, ot does it have to be char or string or whatever.

Depends on what your vector is. You can have a vector of ints, strings, chars, whatever.

// Basic syntax
vector<data_type> identifier;

// Example
vector<int> my_ints;
vector<char> my_chars;
vector<string> my_strings;

[vastrolorde]

i need to make dec to binary converter. and well, the locaritm goes that lets say 18. 18%2 = 0 so the last number in binary must be 0. i want a string that contains these numbers, so each time i get a new 0 or 1 it is added to the begginning of the number.

[JLBorges]

> so each time i get a new 0 or 1 it is added to the begginning of the number.

Either

std::string str = "1011" ;
int number = 18%2 ;
str.insert( str.begin(), '0' + number ) ;

Or

std::string str = "1011" ;
int number = 18%2 ;
str = char( '0' + number ) + str ;