View Compilation Error

0_0_4747461_18470.cpp:6:1: invalid suffix "using" on floating constant
0_0_4747461_18470.cpp:6: error: expected unqualified-id before numeric constant
0_0_4747461_18470.cpp:6: error: expected `,' or `;' before numeric constant
0_0_4747461_18470.cpp: In function `double closest(int, int)':
0_0_4747461_18470.cpp:34: error: `sort' undeclared (first use this function)
0_0_4747461_18470.cpp:34: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4747461_18470.cpp: In function `int main()':
0_0_4747461_18470.cpp:58: error: `sort' undeclared (first use this function)