foo.cpp: In function 'int main()':
foo.cpp:17:22: error: 'abs' was not declared in this scope
foo.cpp:17:22: note: suggested alternative:
In file included from foo.cpp:2:0:
c:\mingw32\bin\../lib/gcc/mingw32/4.7.1/include/c++/cmath:102:5: note:   'std::abs'