View Compilation Error

0_0_16749573_25402.cpp: In function 'int main()':
0_0_16749573_25402.cpp:25:27: error: 'memset' was not declared in this scope
   memset(len,0,sizeof(len));
                           ^
0_0_16749573_25402.cpp:29:21: error: 'strlen' was not declared in this scope
    len[i]=strlen(str);
                     ^