View Compilation Error

0_0_13040268_11827.cpp:1:10: #include expects "FILENAME" or <FILENAME>
0_0_13040268_11827.cpp:2:10: #include expects "FILENAME" or <FILENAME>
0_0_13040268_11827.cpp:3:10: #include expects "FILENAME" or <FILENAME>
0_0_13040268_11827.cpp:5: error: `acos' was not declared in this scope
0_0_13040268_11827.cpp: In function `int main()':
0_0_13040268_11827.cpp:11: error: `scanf' undeclared (first use this function)
0_0_13040268_11827.cpp:11: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_13040268_11827.cpp:17: error: `sqrt' undeclared (first use this function)
0_0_13040268_11827.cpp:17: error: `acos' undeclared (first use this function)
0_0_13040268_11827.cpp:17: error: `printf' undeclared (first use this function)