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How do I terminate character string array?
The following example does not work!!!
void main (void) {
int i;
char *workdays[]={"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "" };
// notice "" - empty string at the end of array
char **work_day;
work_day=workdays;
while (*work_day) printf("%d\n", i++);
exit(1);
}
This example will print numbers from 1 to xxx instead of printing from 1 to 6.
I need explanation why "" at the end of array isn't treated as \n?
Tomislav
Sorry instead of \n should be \0!!!
Hi,
What you had done is u never incremened the pointer to point to the next location. U can do that like this
[ccode]
void main (void) {
int i=0;
char *workdays[]={"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "" };
// notice "" - empty string at the end of array
char **work_day;
work_day=&workdays[0];
while (strlen(*work_day)>0)
{
printf("%s\n", *work_day);
i++;
work_day=&workdays[i];
}
}
[/code]
Regards,
Balaji.
If it helps rate it
Another approach:
int main (void)
{
char *workdays[]={"Monday", "Tuesday", "Wednesday", "Thursday", "Friday"};
for (int i = 0; i < sizeof(workdays)/sizeof(*workdays); ++i)
printf("%d\0", i);
exit(1);
}
Please - rate answer if it helped you
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Best regards,
-----------
Igor Soukhov (Brainbench/Tekmetrics ID:50759)
[email protected] | ICQ:57404554 | http://soukhov.com
Member of Russian Software Developer Network http://rsdn.ru
The simple answer is that '\n' and "" are not the same in C++. Either use '\n' and '\n' or "" and '\0'.
There are two problems with this.
The first as balijj pointed out, is that you are not incrementing work_day, so that it always points to workdays[0]. Since that is never 00, the loop never terminates.
That's easy enough to fixed.while (*work_day++) printf("%d\n", i++);
But that's not going to solve your problem, which is a bit more fundemental.
work_day is a pointer to a char pointer, or, more exactly, a pointer into an array of char pointer. So first work_day points to workdays[0], then, after incrementing, it points to workdays[1], and so on.
workdays[0], workdays[1], etc are themselves pointer. workdays[0] *points* to the text literal "Monday", and workdays[5] *points* to the text literal "".
Now, let's look at your test while (*work_day)
which says "loop until what work_day points to is zero". But work_day only points to char*, and each of the char* in workdays have non-zero values, that is, they all point to something. (What that something is, is irrelevant).
So, we don't want workdays[5] to *point* to a zero. workdays[5] must *be* a zero. The is also easily accomplished:char *workdays[]={"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", 0 };
Truth,
James
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http://www.NovelTheory.com
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