View Compilation Error

0_0_30829264_6915.cpp: In function 'int main()':
0_0_30829264_6915.cpp:20:31: error: 'strlen' was not declared in this scope
               l0=strlen(s[0]+1);
                               ^
0_0_30829264_6915.cpp:22:43: error: 'memset' was not declared in this scope
               memset(_next,0,sizeof(_next));
                                           ^