c++ - what does this line means ? half += string(freq[i] / 2, i + 'a'); -

http://www.geeksforgeeks.org/print-all-palindrome-permutations-of-a-string/

what line mean

half += string(freq[i] / 2, + 'a');  

in code ?

void printallpossiblepalindromes(string str) {     int freq[m];      if (!ispalin(str, freq))         return;      int l = str.length();      string half = "";     char oddc;     (int = 0; < m; i++)     {         if(freq[i] % 2 == 1)             oddc = + 'a';          half += string(freq[i] / 2, + 'a');     }      string palin;          {         palin = half;         if (l % 2 == 1)             palin += oddc;         palin += reverse(half);         cout << palin << endl;     }     while (next_permutation(half.begin(), half.end())); } 

string(freq[i] / 2, + 'a');  

is coming

string (size_t n, char c); 

which fill constructor:

fills string n consecutive copies of character c.

so creating onstance of string class with

size_t n replaced by: freq[i] / 2 , char c i + 'a'

and string object getting concatenated object half when do:

half += string(freq[i] / 2, + 'a');