Hi I was trying to do the following code reversing a string without using arrays but its giving me segmentation fault. I hope you guys can help me out.
#include <strings.h>
#include <string.h>
#include <stdio.h>
void main()
{
char *s, *c;int i,j;
printf("enter the string\n");
scanf("%s", s);
for(i = strlen(s), j = 0; i >= 0, j <= strlen(s); i--, j++){
printf("%c\n", *(s+i));
*(c+j) = *(s + i);
}
}
You aren't allocating any memory for s.
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Thanks a lot for ur help
But it should copy the reversed string s into C itz not doing that
As has been said, s & c doesn't point at any valid memory. You need to allocate some using malloc().
Also, don't forget about the NULL terminator.
MagosX.com
Give a man a fish and you feed him for a day.
Teach a man to fish and you feed him for a lifetime.
Yeah I did allocate memory but still the reversed string S is not being copied into the string c.
<code>
#include<stdlib.h>
#include <strings.h>
#include <string.h>
#include <stdio.h>
void main()
{
char *s, *c;int i, j;
s = (char *)malloc(50);
printf("enter the string\n");
scanf("%s", s);
c = (char *)malloc(strlen(s));
for(i = strlen(s), j = 0; i >= 0; i--){
*(c + j) = *(s + i);
j++;
}
printf("%s", c);
free(s); free(c);
printf("\n");
}
</code>
First, to be able to hold the NULL terminator the size of c must be strlen(s) + 1.
Second, to prevent the first element from being the NULL terminator, start looping at strlen(s) - 1.
Third, you never add a NULL terminator at the end of the array, meaning the string will never end.
MagosX.com
Give a man a fish and you feed him for a day.
Teach a man to fish and you feed him for a lifetime.
Fourth, your code tags are wrong, proving that you either didn't read, or didn't pay attention to, the thread for it.
[code]
...your code here...
[/code]
Fifth, you're using void main, which shows that you are either an idiot, have an idiot for a teacher, or you haven't read the FAQ/countless discussions on it...
Quzah.Code:int main ( ...pick your poison... ) { ...do your damage... return 0; }
Hope is the first step on the road to disappointment.
But strings automatically terminate with a NULL character
Thanx a lot guyz it did work. thanx a lot again
Yes. By definition, a string is a series of one or more characters, terminated by a null. So yes, all strings have a null. However, a given sequence of characters does a string make.Originally posted by kate1234
But strings automatically terminate with a NULL character
The final example does not have a null automaticly. You can act like it's a string, and C will not prevent you from doing so:Code:char *mystring = "This has a null automaticly."; char myarray[] = "This has a null automaticly also."; char my2ndarray[5] = { 'H', 'e', 'l', 'l', 'o' };
This will actually print 'Hello', however, you'll get a bunch of crap on the end because it's not null terminated. (IE: String based functions such as this will try and continue to display or use all characters (ie: bytes of memory) until they finally reach a null.)Code:printf( "%s", my2ndarray );
Quzah.
Hope is the first step on the road to disappointment.
Thanx a lot quzah for making the concepts clear
Sixth, this thread is funny
