Sort stability: Difference between revisions
→{{header|BBC BASIC}}
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LV_ModifyCol(3, "Sort")
Return</lang>
=={{header|AWK}}==
<lang AWK>
# syntax: GAWK -f SORT_STABILITY.AWK [-v width=x] -v field=x SORT_STABILITY.TXT
#
# sort by country: GAWK -f SORT_STABILITY.AWK -v field=1 SORT_STABILITY.TXT
# sort by city: GAWK -f SORT_STABILITY.AWK -v field=2 SORT_STABILITY.TXT
#
# awk sort is not stable. Stability may be achieved by appending the
# record number, I.E. NR, to each key.
#
BEGIN {
FIELDWIDTHS = "4 20" # 2 fields: country city
PROCINFO["sorted_in"] = "@ind_str_asc"
if (width == "") {
width = 6
}
}
{ arr[$field sprintf("%0*d",width,NR)] = $0 }
END {
if (length(NR) > width) {
printf("error: sort may still be unstable; change width to %d\n",length(NR))
exit(1)
}
printf("after sorting on field %d:\n",field)
for (i in arr) {
printf("%s\n",arr[i])
}
exit(0)
}
</lang>
<p>input:</p>
<pre>
UK London
US New York
US Birmingham
UK Birmingham
</pre>
<p>output:</p>
<pre>
GAWK -f SORT_STABILITY.AWK -v field=1 SORT_STABILITY.TXT
after sorting on field 1:
UK London
UK Birmingham
US New York
US Birmingham
GAWK -f SORT_STABILITY.AWK -v field=2 SORT_STABILITY.TXT
after sorting on field 2:
US Birmingham
UK Birmingham
UK London
US New York
</pre>
=={{header|BBC BASIC}}==
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