View Compilation Error

0_0_21849433_18076.cpp: In function 'int main()':
0_0_21849433_18076.cpp:42:26: error: 'memset' was not declared in this scope
    memset(A, 0, sizeof(A));
                          ^
0_0_21849433_18076.cpp:45:20: error: 'strlen' was not declared in this scope
    int n = strlen(A);
                    ^