View Compilation Error

0_0_32505461_25714.cpp: In function 'int main()':
0_0_32505461_25714.cpp:36:23: error: 'memset' was not declared in this scope
   memset(v,0,sizeof(v));
                       ^
0_0_32505461_25714.cpp:39:19: error: 'strlen' was not declared in this scope
   len = strlen(num);
                   ^