View Compilation Error

0_0_14003279_27196.cpp: In function 'int main()':
0_0_14003279_27196.cpp:28:15: error: 'strlen' was not declared in this scope
   n=strlen(A+1),m=strlen(B+1);
               ^
0_0_14003279_27196.cpp:41:28: error: 'memset' was not declared in this scope
    memset(pre,0,sizeof(pre));
                            ^