View Compilation Error

0_0_36693080_26946.cpp: In function 'int main()':
0_0_36693080_26946.cpp:53:75: error: 'strcmp' was not declared in this scope
    while(scanf("%d %s", &target, str) && !((target==0)&&(strcmp(str, "END")==0))) 
                                                                           ^
0_0_36693080_26946.cpp:55:39: error: 'memset' was not declared in this scope
         memset(visit, 0, sizeof(visit));
                                       ^
0_0_36693080_26946.cpp:59:25: error: 'strlen' was not declared in this scope
         len = strlen(str);
                         ^