Compilare: main.cpp: In function 'int main()': main.cpp:16:19: warning: NULL used in arithmetic [-Wpointer-arith] 16 | for(j=0;a[j]!=NULL && a[j]!='\n';j++){ | ^~~~ main.cpp:12:9: warning: unused variable 'n' [-Wunused-variable] 12 | int n,m,i=0; | ^ main.cpp:12:11: warning: unused variable 'm' [-Wunused-variable] 12 | int n,m,i=0; | ^