View Compilation Error

0_0_16960192_11812.cpp: In function 'void init()':
0_0_16960192_11812.cpp:14:31: error: 'memset' was not declared in this scope
     memset(num, 0, sizeof(num));
                               ^
0_0_16960192_11812.cpp: In function 'int main()':
0_0_16960192_11812.cpp:26:28: error: 'strlen' was not declared in this scope
         ll len = strlen(str);
                            ^