Accelerated C++ Exercise 5-5

#include <iostream>#include <string>#include <vector>using namespace std;vector<string> center(const vector<string>& picture) {vector<string> new_picture;vector<string>::size_type max_length = 0;for (vector<string>::const_iterator i = picture.begin(); i != picture.end(); ++i)if (i->size() > max_length)max_length = i->size();for (vector<string>::const_iterator i = picture.begin(); i != picture.end(); ++i) {vector<string>::size_type padding = (max_length - i->size()) / 2;string new_line(padding, ' ');new_line += *i;new_picture.push_back(new_line);}return new_picture;}int main() {vector<string> picture;        picture.push_back("*");picture.push_back("***");picture.push_back("*****");picture.push_back("*******");picture.push_back("*********");vector<string> new_picture = center(picture);for (vector<string>::const_iterator i = new_picture.begin();    i != new_picture.end(); ++i)cout << *i << endl;system("pause");return 0;}