Compilare: user.cpp: In function ‘void read()’: user.cpp:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void pairing(int)’: user.cpp:56: warning: comparison between signed and unsigned integer expressions user.cpp:66: warning: comparison between signed and unsigned integer expressions user.cpp:77: warning: comparison between signed and unsigned integer expressions user.cpp:83: warning: comparison between signed and unsigned integer expressions user.cpp:88: warning: comparison between signed and unsigned integer expressions user.cpp:91: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void write()’: user.cpp:142: warning: comparison between signed and unsigned integer expressions user.cpp:145: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:155: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result