View Compilation Error

0_0_3371622_16984.cpp: In function `int main()':
0_0_3371622_16984.cpp:9: error: `sqrt' undeclared (first use this function)
0_0_3371622_16984.cpp:9: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_3371622_16984.cpp:13: error: expected `}' at end of input