Error(s):

source_file.cpp: In function ‘void single_digit(char*)’:
source_file.cpp:10:7: error: incompatible types in assignment of ‘char*’ to ‘char [10]’
   sum = sum + n[i];
       ^
source_file.cpp:12:10: error: ISO C++ forbids comparison between pointer and integer [-fpermissive]
  if(sum>=10)
          ^
source_file.cpp:15:2: error: expected ‘;’ before ‘}’ token
  }
  ^