View Compilation Error

0_0_17677537_12455.cpp: In constructor 'word::word()':
0_0_17677537_12455.cpp:10:29: error: 'memset' was not declared in this scope
         memset(s,0,sizeof(s));
                             ^
0_0_17677537_12455.cpp: In function 'int main()':
0_0_17677537_12455.cpp:26:23: error: 'strlen' was not declared in this scope
         len=strlen(str);
                       ^
0_0_17677537_12455.cpp:39:23: error: 'strlen' was not declared in this scope
         len=strlen(str);
                       ^