Compilare: user.cpp: In function ‘int main()’: user.cpp:22:22: warning: NULL used in arithmetic [-Wpointer-arith] for(ui i=0;s[i]!=NULL;i++) ^ user.cpp:26:26: warning: NULL used in arithmetic [-Wpointer-arith] for(ui j=0;s[j]!=NULL;j++) ^ user.cpp:19:8: warning: unused variable ‘n’ [-Wunused-variable] ui n=strlen(s)-1; ^ user.cpp:20:8: warning: unused variable ‘m’ [-Wunused-variable] ui m=strlen(s1)-1; ^