View Compilation Error

0_0_31705466_8426.cpp: In function 'int sum(int, int)':
0_0_31705466_8426.cpp:5:19: error: invalid conversion from 'int' to 'const char*' [-fpermissive]
     while(~scanf(a))
                   ^
In file included from 0_0_31705466_8426.cpp:1:0:
GCC4.9.2/x86_64-w64-mingw32/include/stdio.h:386:15: note: initializing argument 1 of 'int scanf(const char*, ...)'
   int __cdecl scanf(const char * __restrict__ _Format,...) __MINGW_ATTRIB_DEPRECATED_SEC_WARN;
               ^