Compilare: user.cpp: In function ‘void printString(std::string)’: user.cpp:43:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < X.size(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:55:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] x[n] = NULL; ^ user.cpp:65:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < w.size(); ++i) { ^ user.cpp:68:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < w[i].size(); ++j) ^ user.cpp:75:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < w.size(); ++i) { ^ user.cpp:88:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < gr[i].size(); ++j) { ^ user.cpp:49:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("litere2.in", "r", stdin); ^ user.cpp:50:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("litere2.out", "w", stdout); ^ user.cpp:52:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(x); ^ /tmp/ccsCJiw0.o: In function `main': user.cpp:(.text.startup+0x56): warning: the `gets' function is dangerous and should not be used.