Compilare: user.cpp: In function ‘int main()’: user.cpp:68: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:73: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:80: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void del(int)’: user.cpp:54: warning: assuming signed overflow does not occur when assuming that (X + c) < X is always false