Compilare: main.cpp: In function 'int main()': main.cpp:69:18: warning: format '%d' expects argument of type 'int', but argument 3 has type 'size_t' {aka 'long unsigned int'} [-Wformat=] 69 | fprintf(w, "%d\n", s); | ~^ ~ | | | | int size_t {aka long unsigned int} | %ld main.cpp:70:21: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 70 | for(int i = 0; i<s; i++) | ~^~