View Compilation Error

0_0_4709622_7311.cpp: In function `void sum()':
0_0_4709622_7311.cpp:8: error: `strlen' undeclared (first use this function)
0_0_4709622_7311.cpp:8: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4709622_7311.cpp:11: error: `memset' undeclared (first use this function)
0_0_4709622_7311.cpp: In function `int main()':
0_0_4709622_7311.cpp:50: error: `memset' undeclared (first use this function)
0_0_4709622_7311.cpp:4: error: too many arguments to function `void sum()'
0_0_4709622_7311.cpp:51: error: at this point in file