Compilare: user.cpp: In function ‘int main()’: user.cpp:66:18: warning: unused variable ‘chr’ [-Wunused-variable] char chr; ^ user.cpp:85:9: warning: unused variable ‘posslib’ [-Wunused-variable] int posslib = -1; ^ user.cpp:57:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("miting.in","r",stdin); ^ user.cpp:58:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("miting.out","w",stdout); ^ user.cpp:60:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n%d %d\n", &op, &n, &m); ^ user.cpp:61:17: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(ss + 1); ^ user.cpp:67:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%c", &s[i][j]); ^ user.cpp:69:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("\n"); ^ /tmp/ccm37rYb.o: In function `main': user.cpp:(.text.startup+0x84): warning: the `gets' function is dangerous and should not be used.