Compilare: user.cpp: In function ‘int main()’: user.cpp:100:30: warning: format ‘%ld’ expects argument of type ‘long int’, but argument 2 has type ‘int’ [-Wformat=] printf("%ld", expr(p)); ^ user.cpp:88:13: warning: unused variable ‘j’ [-Wunused-variable] long i, j; ^ user.cpp:90:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.in", "r", stdin); ^ user.cpp:91:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("bool.out", "w", stdout); ^ user.cpp:92:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:93:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%ld\n", &len); ^ user.cpp:94:14: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(sch); ^ /tmp/ccvzDNqe.o: In function `main': user.cpp:(.text.startup+0x55): warning: the `gets' function is dangerous and should not be used.