Compilare: user.cpp: In function ‘int main()’: user.cpp:17:20: warning: NULL used in arithmetic [-Wpointer-arith] while (p[i] != NULL) ^~~~ user.cpp:23:39: warning: NULL used in arithmetic [-Wpointer-arith] while (p[i] == ' ' && p[i] != NULL) ^~~~ user.cpp:35:20: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] v[0] = NULL; ^~~~ user.cpp:41:24: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] v[++cnt] = NULL; ^~~~ user.cpp:50:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0; j<strlen(v); j++) ~^~~~~~~~~~ user.cpp:55:27: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] a[n][m] = NULL; ^~~~ user.cpp:60:43: warning: NULL used in arithmetic [-Wpointer-arith] while (p[i] == ' ' && p[i] != NULL) ^~~~ user.cpp:74:43: warning: NULL used in arithmetic [-Wpointer-arith] while (p[i] == ' ' && p[i] != NULL) ^~~~