Compilare: user.cpp: In function ‘int main()’: user.cpp:124:33: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘const char*’ [-Wformat=] else fprintf(g, "%d\n", "-1"); ^ user.cpp:89:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d%d\n", &r ,&c); ^ user.cpp:92:30: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(1 + a[i], M, f); ^