View Compilation Error

0_0_14794400_16727.cpp: In function 'int main()':
0_0_14794400_16727.cpp:10:14: error: 'pow' was not declared in this scope
   d=pow(d,0.5);
              ^
0_0_14794400_16727.cpp: At global scope:
0_0_14794400_16727.cpp:15:1: error: expected unqualified-id before '--' token
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 ^