macOS "Expression result unused" Help?!

[raaron1990]

Hi all,

Hopefully someone can help me out. I'm new to programming, and for class, we have to make a program that determines the day of the week of a specific date that the user enters. I keep getting an error "expression result unused" and I can't figure out why. Here's part of my source code:

int month, day, years, LTYear, total, Gtotal;
    
    cout<<"Input date in M/DD/YYYY format. (ex. 2/07/1990 or 10/13/2010)"<<endl;
    cin>>month; day; years;
    
    if (month==2 && years%4==0 && years%100!=0 && day>=30)
        cout<<"Invalid day.\n";
    else if (month==2 && day>=29)
        cout<<"Invalid day.\n";
    
    if (day<=1||day>31)
        cout<<"Invalid day.\n";
    
    if (years<1900 || years>2099)
        cout<<"Invalid year.\n";

I get the issue when I try to get the cin for day and year. Any advice?

Thanks in advance!

 

[knightlie]

I'm not a C programmer, but this:

cin>>day; month; year;

looks wrong to me - that appears to be three statements:

cin>>day;
month;
year;

A semi-colon marks the end of a statement. The compiler is complaining that the month; and year; statements do not do anything. Maybe it should be:

cin>>day, month, year;

Edit: Yes, the cin line is incorrect. As this is for class I won't give you the answer ( ), but you need to change that line to be able to populate multiple variables.

 

[gnasher729]

Hi all,

Hopefully someone can help me out. I'm new to programming, and for class, we have to make a program that determines the day of the week of a specific date that the user enters. I keep getting an error "expression result unused" and I can't figure out why. Here's part of my source code:

int month, day, years, LTYear, total, Gtotal;
    
    cout<<"Input date in M/DD/YYYY format. (ex. 2/07/1990 or 10/13/2010)"<<endl;
    cin>>month; day; years;[/QUOTE]

The golden rule: Don't ask yourself what is wrong with your compiler. Ask yourself what is wrong with your code. I'm sure Xcode gave you a precise location of the problem. 

When I write statements, I'll almost always write them on separate lines. Then the last three statements become

[CODE]    cin >> month;
    day;
    years;

There are three statements. What does each of them do?