How to extract last 3 digit of an array of a string and store it to different int array in C

Question

I want to extract last 3 digit of a string suppose like :

char a[100][100] = ["17BIT0111" , "17BIT0222", ... n];

and I want to take last three digits and store in different array like

int b[100] =[111 , 222 , ... n];

I took reference from this but I wan't it without using pointer or a linked list. As I am gonna use it for comparing stack. C program to extract different substrings from array of strings

you can't do anything without pointers - you need to go over your string somehow. But you don't need to dynamically allocate memory since your array sizes are hardcoded — Ora, Dec 14 '17 at 16:13
@Ora by minimal use of pointer ? Or can't we extract here by performing nested loop or substring ? — Vivank, Dec 14 '17 at 16:15

unwind · Answer 1 · 2017-12-14T16:29:52.230

1

Something like this:

for (int i = 0; i < 100; ++i)
{
  unsigned int value = 0;
  sscanf(a[i], "17BIT%u", &value);
  b[i] = (int) (value % 1000);
}

This doesn't check the return value of sscanf(), instead defaulting the value to 0 in case conversion fails.

This will convert a larger integer, so the % 1000 was added to make sure only the last three digits really matter in the conversion. The unsigned is simply to disallow embedded dashes in the string, which makes sense to me in cases like these.

edited Dec 14 '17 at 16:29

answered Dec 14 '17 at 16:17

unwind

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Will it extract the last 3 digit ? and store in b ? – Vivank Dec 14 '17 at 16:20
@Vivank.: Don't edit the question after an answer is posted. Ask new question. – user2736738 Dec 14 '17 at 16:31
So if it's last 4 digit it would be % 10000 ? – Vivank Dec 14 '17 at 16:36
@Vivank Yes, but only if there can be more that you want to get rid of, I don't know your input so perhaps the entire `%` step is pointless. It will convert the number after the `17BIT` prefix, basically. – unwind Dec 14 '17 at 16:39
@unwind My input is in the format of "17BIT0111" so according to me without '%' step also we can do it. – Vivank Dec 14 '17 at 16:46
@Vivank Sure, but that will convert all four digits, so if you have `"17BIT9999"` you will get `9999` stored. – unwind Dec 14 '17 at 16:47
What about 0999 ? – Vivank Dec 14 '17 at 16:49
@Vivank - why not run it to find out? That's what a debugger (or iterative development) can tell you. – KevinDTimm Dec 14 '17 at 17:06

How to extract last 3 digit of an array of a string and store it to different int array in C

1 Answers1