View Compilation Error

0_0_36830345_13433.cpp:12:10: error: 'int add' redeclared as different kind of symbol
 int add(n)
          ^
0_0_36830345_13433.cpp:2:5: note: previous declaration 'int add(int)'
 int add(int n);
     ^
0_0_36830345_13433.cpp:12:9: error: 'n' was not declared in this scope
 int add(n)
         ^