sudoku.cpp: In function 'void bck(int)': sudoku.cpp:40: warning: suggest explicit braces to avoid ambiguous 'else' sudoku.cpp: In function 'int main()': sudoku.cpp:55: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x sudoku.cpp:55: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x