View Compilation Error

226199_0_18636.cpp: In function `int main()':
226199_0_18636.cpp:6: error: `cin' undeclared (first use this function)
226199_0_18636.cpp:6: error: (Each undeclared identifier is reported only once for each function it appears in.)
226199_0_18636.cpp:10: error: `cout' undeclared (first use this function)
226199_0_18636.cpp:10: error: `endl' undeclared (first use this function)
226199_0_18636.cpp:12: error: `sqrt' undeclared (first use this function)