change place of last column but getting new line - awk

Question

I have a file separated by \t.
header text with many lines
V F A B
10 30 26 42
14 33 25 45
16 32 23 43
18 37 22 48
I want to change the 3rd column by the 4th and vice versa. I'm using
awk '
BEGIN {
RS = "\n";
OFS="\t";
record=0;
};
record {
a = $4;
$4 = $3;
$3 = a;
};
$1=="V" {
record=1
};
{
print $0
};
'
}
Instead of just changing the position of the columns, column 3 also has the line break of the original 4th column:
header text with many lines
V F A B
10 30 42
26
14 33 45
25
16 32 43
23
18 37 48
22
How can I prevent this in order to get?
header text with many lines
V F A B
10 30 42 26
14 33 45 25
16 32 43 23
18 37 48 22

Answer 1

Could you please try following, using usual method of storing 1 field's value to a variable and then exchanging the value of 4th field to 3rd field, at last putting 4th field value as variable value(could say swapping values using a variable).
awk 'FNR==1{print;next} {val=$3;$3=$4;$4=val} 1' OFS="\t" Input_file

Answer 2

Or, this messy sed:
sed -E 's/([[:digit:]]+)([[:blank:]]+)([[:digit:]]+)([[:space:]]*)$/\3\2\1\4/' file
# ^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^
# 3rd column tab 4th column optional whitespce