Question and Answers

1. How do I convert a string to upper case?

To convert a C++ string to upper case you would need to process each char, e.g., something like


#include <cctype>

   ...

 for(int i = 0; i < s.length(); ++i){

      s[i] = toupper(s[i]);

 }


   #include <cctype>

   ...

   for(string::iterator p = s.begin(); p != s.end(); ++p){

         *p = toupper(*p);

   }

2. How do I make a two-dimensional table/matrix/array using vector?

A matrix is just a vector of vectors, that is, a matrix is a vector of rows where each row is a vector of ints, doubles, or whatever. Thus it's pretty intuitive to write


	vector< vector<int> >

but one "gotcha" is that there must be a space between the '>' characters, to avoid confusion with the >> operator.

Also, initialization to specify the number of rows and columns is done like this:


	vector< vector<int> >m(2, vector<int>(3));	//2 rows of 3 columns each

// Don't forget the space between the '>' characters!

Now m[i][j] refers to the ith row and jth column of m.

To access the whole table m you can use nested loops like this:


for(int row=0; row<m.size(); ++row){

  for(int column=0; column<m[row].size(); ++column){

    cout << m[row][column] << ' ';

  }

  cout << endl;

}

Last modified 04/18/2008