View Compilation Error

0_0_2046322_7103.cpp: In function `double dis(double, double, double, double)':
0_0_2046322_7103.cpp:4: error: `sqrt' undeclared (first use this function)
0_0_2046322_7103.cpp:4: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2046322_7103.cpp: In function `double solve()':
0_0_2046322_7103.cpp:18: error: `swap' undeclared (first use this function)
0_0_2046322_7103.cpp:19: error: `random_shuffle' undeclared (first use this function)
0_0_2046322_7103.cpp:29: error: `reverse' undeclared (first use this function)
0_0_2046322_7103.cpp: In function `int main()':
0_0_2046322_7103.cpp:41: error: `scanf' undeclared (first use this function)
0_0_2046322_7103.cpp:45: error: `printf' undeclared (first use this function)