Compilare: user.c: In function ‘main’: user.c:18:9: warning: implicit declaration of function ‘strlen’ [-Wimplicit-function-declaration] for(int j = 0; j < strlen(line); ++j) ^ user.c:18:28: warning: incompatible implicit declaration of built-in function ‘strlen’ [enabled by default] for(int j = 0; j < strlen(line); ++j) ^ user.c:38:13: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 3 has type ‘int’ [-Wformat=] fprintf(g,"%lld", MIN(k[0], k[1]) * MIN(k[2], k[3])); ^ user.c:40:9: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 3 has type ‘int’ [-Wformat=] fprintf(g,"%lld\n", MIN(k[0], k[1]) * MIN(k[2], k[3])); ^ user.c:12:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file, "%i", &n); ^ user.c:14:10: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(line, sizeof(line), file); ^ user.c:17:14: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(line, sizeof(line), file); ^