View Compilation Error

0_0_14054758_14510.cpp: In function 'int main()':
0_0_14054758_14510.cpp:13:33: error: 'memset' was not declared in this scope
         memset(str,0,sizeof(str));
                                 ^
0_0_14054758_14510.cpp:16:35: error: 'strlen' was not declared in this scope
         int j=0,i=0,len=strlen(str);
                                   ^