Compilare: user.cpp: In function ‘int main()’: user.cpp:62:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < strlen(S); i++) ^ user.cpp:55:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("compresie.in", "r", stdin); ^ user.cpp:56:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("compresie.out", "w", stdout); ^ user.cpp:60:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(S); ^ /tmp/ccqtgPyN.o: In function `main': user.cpp:(.text.startup+0x5b): warning: the `gets' function is dangerous and should not be used.