Compilare: user.cpp: In function ‘void add(int, int)’: user.cpp:32: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int exist(int, int)’: user.cpp:46: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:66: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:68: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result user.cpp:76: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:79: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result