View Compilation Error

0_0_30765029_4049.cpp: In function 'int main()':
0_0_30765029_4049.cpp:7:9: error: storage size of 'n' isn't known
  char n[];
         ^
0_0_30765029_4049.cpp:8:9: error: storage size of 'm' isn't known
  char m[];
         ^