qsort Post: 302082446

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Top Forums Programming qsort Post 302082446 by areef4u on Wednesday 2nd of August 2006 08:43:46 AM

08-02-2006

Registered User

qsort

this is the code in K & R ritchie

void qsort(int v[], int left, int right){
int i, last;
void swap(int v[], int i, int j);

if(left >= right)
return;
swap(v, left, (left + right)/2);
last = left;
for(i = left + 1; i <= right; i++)
if(v[i] < v[left])
swap(v, ++last,i); swap(v, left, last);
qsort(v , left, last - 1);
qsort(v, last - 1, right);
}

the highlighted portion does not make sense to me at the first go, b'cos it is trying to swap the same element. i find (i & last ) have the same value when swap is called in the for loop for the first time, plz explain....

thanks in advance

areef4u

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operator

OPERATOR(7)                                                  Linux Programmer's Manual                                                 OPERATOR(7)

NAME

       operator - C operator precedence and order of evaluation

DESCRIPTION

       This manual page lists C operators and their precedence in evaluation.

       Operator                            Associativity
       () [] -> .                          left to right
       ! ~ ++ -- + - (type) * & sizeof     right to left
       * / %                               left to right
       + -                                 left to right
       << >>                               left to right
       < <= > >=                           left to right
       == !=                               left to right
       &                                   left to right
       ^                                   left to right
       |                                   left to right
       &&                                  left to right
       ||                                  left to right
       ?:                                  right to left
       = += -= *= /= %= <<= >>= &= ^= |=   right to left
       ,                                   left to right

COLOPHON

       This  page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Linux                                                               2011-09-09                                                         OPERATOR(7)

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operator