View Compilation Error

0_0_4961664_16055.cpp: In function `int main()':
0_0_4961664_16055.cpp:9: error: `scanf' undeclared (first use this function)
0_0_4961664_16055.cpp:9: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4961664_16055.cpp:12: error: `memset' undeclared (first use this function)
0_0_4961664_16055.cpp:17: error: `strlen' undeclared (first use this function)
0_0_4961664_16055.cpp:35: error: `printf' undeclared (first use this function)