View Compilation Error

0_0_24381349_31134.cpp: In function 'int main()':
0_0_24381349_31134.cpp:6:20: error: cannot convert 'char (*)[1000]' to 'char*' for argument '1' to 'char* gets(char*)'
     while(gets(&str)!=EOF){
                    ^
0_0_24381349_31134.cpp:41:35: error: 'memset' was not declared in this scope
         memset(flag,0,sizeof(flag));
                                   ^
0_0_24381349_31134.cpp:46:44: error: 'strcmp' was not declared in this scope
                 if(strcmp(words[i],words[j])==0){
                                            ^