View Compilation Error

0_0_17313820_2208.cpp:1:19: error: 'acos' is not a member of 'std'
 const double pi = std::acos(-1.0);  
                   ^
0_0_17313820_2208.cpp: In function 'long long int solve(int)':
0_0_17313820_2208.cpp:23:22: error: 'atan2' is not a member of 'std'
             ang[j] = std::atan2((double)  
                      ^
0_0_17313820_2208.cpp:26:9: error: 'sort' is not a member of 'std'
         std::sort(ang + 1, ang + n);  
         ^
0_0_17313820_2208.cpp: In function 'int main()':
0_0_17313820_2208.cpp:43:5: error: '::scanf' has not been declared
     ::scanf("%d", &z);  
     ^
0_0_17313820_2208.cpp:45:23: error: 'scanf' was not declared in this scope
         scanf("%d", &n);  
                       ^
0_0_17313820_2208.cpp:49:35: error: 'printf' was not declared in this scope
         printf("%I64d\n", solve(n));  
                                   ^