Compilare: user.cpp: In function ‘void read()’: user.cpp:31: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:47: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void pairing(int)’: user.cpp:64: warning: comparison between signed and unsigned integer expressions user.cpp:74: warning: comparison between signed and unsigned integer expressions user.cpp:87: warning: comparison between signed and unsigned integer expressions user.cpp:90: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void dfs(int, int)’: user.cpp:137: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void write()’: user.cpp:184: warning: comparison between signed and unsigned integer expressions user.cpp:189: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:199: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result