View Compilation Error

0_0_12911583_22120.cpp: In function `int main()':
0_0_12911583_22120.cpp:5: error: `scanf' undeclared (first use this function)
0_0_12911583_22120.cpp:5: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_12911583_22120.cpp:7: error: `log' undeclared (first use this function)
0_0_12911583_22120.cpp:10: error: `printf' undeclared (first use this function)