foo.cpp: In function 'int main()':
foo.cpp:13:10: error: 'i' was not declared in this scope
     for (i=1;i<=n;i++)
          ^
foo.cpp:27:15: error: invalid conversion from 'int' to 'const char*' [-fpermissive]
     printf(ans);
               ^
In file included from c:\mingw\lib\gcc\mingw32\4.8.1\include\c++\cstdio:42:0,
                 from foo.cpp:1:
c:\mingw\include\stdio.h:293:37: error:   initializing argument 1 of 'int printf(const char*, ...)' [-fpermissive]
 _CRTIMP int __cdecl __MINGW_NOTHROW printf (const char*, ...);
                                     ^