Compilare: main.cpp: In function 'void prel()': main.cpp:41:19: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 41 | for (i = 0; i < strlen(s); ++i) | ~~^~~~~~~~~~~ main.cpp:49:24: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] 49 | b[k] = NULL; | ^~~~ main.cpp:61:24: warning: converting to non-pointer type 'char' from NULL [-Wconversion-null] 61 | b[k] = NULL; | ^~~~ main.cpp:95:15: warning: unused variable 'aux' [-Wunused-variable] 95 | int x, y, aux(cfol), z(0); | ^~~ main.cpp:95:26: warning: unused variable 'z' [-Wunused-variable] 95 | int x, y, aux(cfol), z(0); | ^ main.cpp: In function 'void afis()': main.cpp:152:12: warning: unused variable 'y' [-Wunused-variable] 152 | int x, y, aux(cfol), z(0); | ^ main.cpp:152:15: warning: unused variable 'aux' [-Wunused-variable] 152 | int x, y, aux(cfol), z(0); | ^~~ main.cpp:152:26: warning: unused variable 'z' [-Wunused-variable] 152 | int x, y, aux(cfol), z(0); | ^