Compilare: user.cpp: In function ‘void read()’: user.cpp:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void pairing(int)’: user.cpp:58: warning: comparison between signed and unsigned integer expressions user.cpp:68: warning: comparison between signed and unsigned integer expressions user.cpp:81: warning: comparison between signed and unsigned integer expressions user.cpp:84: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void write()’: user.cpp:138: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:148: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result