How to get an input from user as an integers array in C?

Question

I'm new to C, currently studying it on CS50 course on edx.org (this task is NOT from CS50 course).

I wrote the program which asks the user for a date of birth, and then calculates a current age depending on system date.

Now I'm getting values from user this way (GetInt() and GetString() are functions from cs50.h header and library).

// Ask user for his name, and date of birth

printf("Enter your name: ");
char* name = GetString();

printf("Enter your day of birth: ");
int birth_day = GetInt();

printf("Enter your month of birth: ");
int birth_month = GetInt();

printf("Enter your year of birth: ");
int birth_year = GetInt();

But I don't want to ask user 3 times to get a date that he can enter as one line - 18.06.1985 for example.

So the question is - how to get input from user in format DD.MM.YYYY, then store it in the array of integers, as [0, 1, 2], so I would be able to access these values separately later on?

You can use a string to take input and then tokenize it and store value in integer variables. — ameyCU, Feb 06 '16 at 11:22
Thank you, but how to do it? Is there more direct way using scanf or something? — Nikita K., Feb 06 '16 at 11:25

score 3 · Answer 1 · answered Feb 06 '16 at 11:28

3

You can do the following:

int array[3];
scanf("%d.%d.%d", &array[0], &array[1], &array[2]);

On an input of 18.06.1990, array[0] will contain 18, array[1] will contain 6 and array[2] will have 1990.

answered Feb 06 '16 at 11:28

KKishore

452
5
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Thank you, this is also right, but if this works, i even don't need an array! – Nikita K. Feb 06 '16 at 11:38
Don't forget to check that `scanf()` returned `3` before using the values. (@NikitaK. — you're right that you don't have to use an array; you can use any three distinct variables.) Life gets more interesting if you want to be flexible about the date format, so you want to allow DD/MM/YYYY and DD MM YYYY as well as DD.MM.YYYY format (and still more interesting if you want to allow DDMMYYYY — let alone YYYY-MM-DD too, or MM/DD/YYYY, or …) Dates are endlessly entertaining (for a very low grade of entertainment value). – Jonathan Leffler Jul 31 '16 at 15:24

score 1 · Accepted Answer · answered Feb 06 '16 at 11:24

1

Create a struct to get that:

typedef struct {
    int day;
    int month;
    int year;
} birthDay;

When you're going to ask the user, you can do:

int day, month, year;
printf("Type your birthday (day month year): ");
scanf("%d %d %d", &day, &month, &year);

Now, you can set your struct properly.

birthday bday;
bday.day = day;
bday.month = month;
bday.year = year;

answered Feb 06 '16 at 11:24

Paulo

1,458
2
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Thank you, this helps! I just didn't know how to use scanf() propertly – Nikita K. Feb 06 '16 at 11:37
2

Note that you should check the return value of `scanf`: if the user gave proper input, 3 numbers optionally separated by white space, the return value will be 3, otherwise, some of the variables `day`, `month`, year` may not have be set at all. – chqrlie Feb 06 '16 at 11:40

How to get an input from user as an integers array in C?

2 Answers2