why this c++ code gives such output? - 


#include<bits/stdc++.h> using namespace std;  string str ; string str ;  int main(){      for(int i=0;i<6;i++)    /// 012345         str[i] = + '0'  ;      for(int j=0;j<6;j++)    /// abcdef         str[j] = j + 'a' ;      cout << str << "  " << str << endl ; /// blank line !!!       printf("%s\n",str.c_str()); /// abcdef     printf("%s\n",str.c_str()); /// abcdef      return 0; }

output ::

 abcdef abcdef

i expect ::

 012345 abcdef 012345 abcdef

you have undefined behavior!

the strings declare empty, , indexing of them out of bounds.

instead should append characters string, either using append member function or += operator.


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