CODEWITHSUNDEEP
cscanf
Matam
Matam

Reputation: 145

Scanf with a specific format

I would like to allow the user to only put input in a specific format.
The format:
a=1,b=-2,c=3 for example. Spaces are allowed inbetween the commas and the characters.
I'm using: if (scanf("a=%lf,b=%lf,c=%lf",&a,&b,&c) == 1) but for some reason it doesn't work. How can I fix it?

Upvotes: 0

Views: 348

Answers (2)

chqrlie
chqrlie

Reputation: 144550

You are converting 3 numbers, the return value should be 3 if all conversions are successful. Also note that %lf ignores spaces before the number. If you also want to ignore spaces around the , and before the = or the a, add a space in the format string:

double a, b, c;

if (scanf(" a =%lf , b =%lf , c =%lf", &a, &b, &c) == 3) {
    /* conversion was successful, 3 numbers parsed */
    ...
}

Note however that scanf() will not ignore just space characters, it will ignore and whitespace characters, including newlines, tabs, etc.

Upvotes: 1

Žiga Sajovic
Žiga Sajovic

Reputation: 324

From the documentation on scanf

Return value

If successful, the total number of characters written is returned, otherwise a negative number is returned.

Try

if (scanf("a=%lf , b=%lf , c=%lf",&a,&b,&c)==3)

You must include empty spaces in the string scanf takes as an argument, specifying the format.

Upvotes: 1

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