I am implementing a program where I want to store only certain part of the input string.
for eg if the input string is
0123456789
I want to discard 4 AND 7
and store
01235689
Please my program requires an input string of 10000 characters so running time is very crucial for me.
Also while inputting the string I really don't know how many characters will be there.
Does anybody have any suggestions?
Any help will be greatly appreciated
swissknife007 3 Junior Poster in Training
gerard4143 371 Nearly a Posting Maven
Depends, what is the criteria for discarding characters.
swissknife007 3 Junior Poster in Training
Depends, what is the criteria for discarding characters.
I already told you the criteria.
I dont want 4s and 7s in my answer
swissknife007 3 Junior Poster in Training
I already told you the criteria.
I dont want 4s and 7s in my answer
I mean I don't want to store 4s and 7s present in the input.
gerard4143 371 Nearly a Posting Maven
I would investigate a function like
void *memchr(const void *s, int c, size_t n);The memchr() function scans the first n bytes of the memory area
pointed to by s for the character c. The first byte to match c
(interpreted as an unsigned character) stops the operation.
The memchr() and memrchr() functions return a pointer to the match‐
ing byte or NULL if the character does not occur in the given mem‐
ory area.
Copied from the manpages on GNU/Linux.
With this function you can leap through valid areas of data to store.
swissknife007 3 Junior Poster in Training
I would investigate a function like
void *memchr(const void *s, int c, size_t n);The memchr() function scans the first n bytes of the memory area
pointed to by s for the character c. The first byte to match c
(interpreted as an unsigned character) stops the operation.The memchr() and memrchr() functions return a pointer to the match‐
ing byte or NULL if the character does not occur in the given mem‐
ory area.Copied from the manpages on GNU/Linux.
With this function you can leap through valid areas of data to store.
Sorry but you didnt understand my question.i dont want to stop reading once i encounter 4 or 7.I want to continue reading the rest of the string
gerard4143 371 Nearly a Posting Maven
Sorry but you didnt understand my question.i dont want to stop reading once i encounter 4 or 7.I want to continue reading the rest of the string
Yes I understood your question. You use the function memchr to find the occurrence of characters(or pointers to the occurrences) to find ranges(pointer ranges) of valid data.
L7Sqr 227 Practically a Master Poster
How are you handling the input/output? Given that you can read from stdin and write to stdout why not just filter the input?
int main () {
int c = 0;
while (EOF != (c = fgetc (stdin))) {
switch (c) {
case '4': case '7': break;
default: fputc (c, stdout);
}
}
return 0;
}
mhd_arif123 0 Newbie Poster
I am implementing a program where I want to store only certain part of the input string.
for eg if the input string is
0123456789
I want to discard 4 AND 7
and store
01235689
Please my program requires an input string of 10000 characters so running time is very crucial for me.
Also while inputting the string I really don't know how many characters will be there.
Does anybody have any suggestions?
Any help will be greatly appreciated
Step 1 : you have to store those characters (that you want to discard) in a data structure
Step 2 : extract a single character from the input string and match it with the list of discardable characters.
Step 3 : if match is not found , copy the extracted character to a new place(datastructure). else leave it.
continue above steps , till the end of input string.
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