Compilare: user.cpp: In function ‘int main()’: user.cpp:90: warning: comparison between signed and unsigned integer expressions user.cpp:92: warning: comparison between signed and unsigned integer expressions user.cpp:94: warning: comparison between signed and unsigned integer expressions user.cpp:81: warning: unused variable ‘sum’ user.cpp:109: warning: comparison between signed and unsigned integer expressions user.cpp:111: warning: comparison between signed and unsigned integer expressions user.cpp:113: warning: comparison between signed and unsigned integer expressions user.cpp:100: warning: unused variable ‘sum’ user.cpp:24: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:25: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:30: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result /tmp/ccY2qRHr.o: In function `main': user.cpp:(.text+0x116): warning: the `gets' function is dangerous and should not be used.