Arash Arash - 1 year ago 62
C Question

statements out of while loop does not run

I am practicing C by following code:

char* streverse(char* s){
int len=strlen(s);
int i=0; int j=len;
char* r;

i++; j--;
printf("\nReverse string is %s",s);
return r;

But the printf never executes. If I remove the:


printf executes. This is strange because while loop ends anyway independent of above assignment. Any clues why printf doesn't execute with above assignment present?


By correcting the printf signature now it prints.

Answer Source

You should set j to len-1 as a first change, since otherwise you're accessing s outside its contents. More precisely, s[len] is going to be a NUL (or character \0), since that's how strings are stored in C. And it is going to be swapped with the first element of the s, effectively making it a zero-length string / empty string.

Second, the format should just be printf("\nReverse string is %s", s);

Also, you should assign r to something before returning it (to s probably?), otherwise it's just going to be initialised to gibberish and cause problems down the line when you try to use it as a pointer.

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