How to parse simple string in C?

Question

I have a string with the following format:

start 123

I am parsing it that way:

if (strstr(line, "start") == line) {
    int number = -1;

    if (sscanf(line + strlen("start "), "%d", &number) == 1) {
        printf("start %d\n", number);
    }
}

Is there any better way in C?

You could write your own parser or try using strtok(). sscanf() is probably the best way though. — james82345
– james82345, Commented Apr 18, 2013 at 13:24

MOHAMED · Accepted Answer · 2013-04-18 13:39:16Z

10

yes you can use only this:

if (sscanf(line, "start %d", &number ) == 1) {

no need for

if (strstr(line, "start") == line) {

any more

If you want to check more: Check that there is no extra characters after the number , then you can use the following format:

char c;
if (sscanf(line, "start %d%c", &number,  &c) == 1) {

Note: the above formats (and even yours) do not check that there is only 1 space between "start" and the number. so if your string is something like "start \t 45" then the if will return true

edited Apr 18, 2013 at 13:39

answered Apr 18, 2013 at 12:59

MOHAMED

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2 Comments

MOHAMED Over a year ago

@Петр Широков note that this format do not check that there is only 1 space between "start" and the number.

Петр Широков Over a year ago

That is ok. In my case the number of spaces does not matter.

BLUEPIXY · Accepted Answer · 2013-04-18 13:04:13Z

0

if (strstr(line, "start") == line) {
    int number = -1;

    if (sscanf(line, "%*s %d", &number) == 1) {
        printf("start %d\n", number);
    }
}

answered Apr 18, 2013 at 13:04

BLUEPIXY

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