View Compilation Error

0_0_9095191_9662.cpp:1: error: expected constructor, destructor, or type conversion before '<' token
0_0_9095191_9662.cpp:1: error: expected `,' or `;' before '<' token
0_0_9095191_9662.cpp: In function `int main()':
0_0_9095191_9662.cpp:7: error: `scanf' undeclared (first use this function)
0_0_9095191_9662.cpp:7: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_9095191_9662.cpp:13: error: `sqrt' undeclared (first use this function)
0_0_9095191_9662.cpp:14: error: `acos' undeclared (first use this function)
0_0_9095191_9662.cpp:16: error: `printf' undeclared (first use this function)