View Compilation Error

0_0_2010731_7475.cpp: In function `int main()':
0_0_2010731_7475.cpp:3: error: `scanf' undeclared (first use this function)
0_0_2010731_7475.cpp:3: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_2010731_7475.cpp:4: error: `printf' undeclared (first use this function)
0_0_2010731_7475.cpp:13: error: `system' undeclared (first use this function)