Compilare: main.cpp: In function 'int main()': main.cpp:15:16: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 15 | for (i = 0; i < strlen(s); ++i) | ~~^~~~~~~~~~~ main.cpp:21:22: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 21 | for (int j = i; j < strlen(s); ++j) | ~~^~~~~~~~~~~ main.cpp:28:11: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] 28 | b[k] = NULL; | ^~~~ main.cpp:44:6: warning: unused variable 'z' [-Wunused-variable] 44 | int z(0); | ^