Compilare: main.cpp: In function 'void add(char*, char*, char*)': main.cpp:53:19: warning: passing NULL to non-pointer argument 2 of 'void* memset(void*, int, size_t)' [-Wconversion-null] 53 | memset(q, NULL, sizeof(q)); | ^~~~ In file included from /usr/include/c++/10/cstring:42, from main.cpp:2: /usr/include/string.h:61:37: note: declared here 61 | extern void *memset (void *__s, int __c, size_t __n) __THROW __nonnull ((1)); | ~~~~^~~ main.cpp: In function 'int main()': main.cpp:121:19: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 121 | for(int i=0; i<strlen(sol); i++) | ~^~~~~~~~~~~~