Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:13:19: error: ‘strlen’ was not declared in this scope int N = strlen(s1), M = strlen(s2); ^ user.cpp:17:13: error: ‘M’ was not declared in this scope while (j < M) ^ user.cpp:13:6: warning: unused variable ‘N’ [-Wunused-variable] int N = strlen(s1), M = strlen(s2); ^