foo.cc: In function 'int main()':
foo.cc:7:5: warning: variable 'day1' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
     ^~~~
foo.cc:7:10: warning: variable 'day2' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
          ^~~~
foo.cc:7:15: warning: variable 'day3' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
               ^~~~
foo.cc:7:20: warning: variable 'day4' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
                    ^~~~
foo.cc:7:25: warning: variable 'day5' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
                         ^~~~
foo.cc:7:30: warning: variable 'day6' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
                              ^~~~
foo.cc:7:35: warning: variable 'day7' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
                                   ^~~~
foo.cc:7:40: warning: variable 'day8' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
                                        ^~~~
foo.cc:7:45: warning: variable 'day9' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
                                             ^~~~
foo.cc:7:50: warning: variable 'day10' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
                                                  ^~~~~
foo.cc:7:56: warning: variable 'day11' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
                                                        ^~~~~
foo.cc:7:62: warning: variable 'day12' set but not used [-Wunused-but-set-variable]
 int day1,day2,day3,day4,day5,day6,day7,day8,day9,day10,day11,day12;
                                                              ^~~~~
foo.cc:27:1: warning: 'daym' is used uninitialized in this function [-Wuninitialized]
 if (d>daym)
 ^~