How to read numbers (separated by spaces) into an array?

Question

Input (getline): 100 231 144 123 551

tab[0] = 100;
tab[1] = 231;

...

How I can do this ?

You most like want to split the string and then do the assigment: http://stackoverflow.com/questions/236129/how-to-split-a-string-in-c — frlan, Feb 01 '14 at 23:51

score 3 · Accepted Answer · answered Feb 01 '14 at 23:59

std::cin >> i breaks on whitespace by default. If you want to handle things on a per-line basis, you could use a std::istringstream.

If the line is mutable, you can just replace spaces with zeros, counting elements on the way if you want a single correct allocation, and use atoi on a second pass..

score 1 · Answer 2 · answered Feb 02 '14 at 00:11

The stupid way is to read the string byte-by-byte and do the translation yourself.

Or you can use sscanf:

char input[] = "100 231 144 123 551" sscanf(input, "%d%d%d%d%d", tab[0], tab[1], tab[2], tab[3], tab[4]);

But I guess you are actually using getline of an istream object - if this is the case, you may just use the operator >> instead:

if it is the standard input stream cin:

cin>>tab[0]>>tab[1]>>...

or, if it is a file stream fin:

fin>>tab[0]>>tab[1]>>...

In the above, I always suppose that you know the number of numbers in the array. If you don't, then you should have something as symbol of termination - then basically you just read numbers until encounter the symbol. It will then depend on what exactly is the symbol.

Way to treat the guy that spends his time giving you the most detailed answer. By the way you said "array", which has static size. So you absolutely *do* know how many numbers to scan. — tenfour, Feb 02 '14 at 14:00

How to read numbers (separated by spaces) into an array?

2 Answers2