Compilare: user.cpp: In function ‘void Solve1()’: user.cpp:50:47: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0; j < HASH[ hashVal_1 ].size(); ++j) ^ user.cpp:39:18: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(sir); ^ user.cpp: In function ‘void Solve2()’: user.cpp:70:18: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(sir); ^ user.cpp: In function ‘int main()’: user.cpp:96:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &op); ^ user.cpp:97:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &n); ^ user.cpp:98:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(S); ^ /tmp/ccSnpJcs.o: In function `Solve1()': user.cpp:(.text+0x12f): warning: the `gets' function is dangerous and should not be used.