Puppy Linux Discussion Forum

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a="2"
for ((z=0; z<65; z++)); do 
b="2"; y=""; 
for ((x=${#a}-1; x>=0; x--)); do y+="${a:$x:1} "; done; ar0=($y); w=""; 
for ((v=${#b}-1; v>=0; v--)); do w+="${b:$v:1} "; done; ar1=($w); c=""; 
for ((y=0; y<${#a}; y++)); do for ((x=0; x<${#b}; x++)); do 
d=${ar0[$y]}$(for ((w=0; w<$y; w++)); do echo -n "0"; done); 
e=${ar1[$x]}$(for ((v=0; v<$x; v++)); do echo -n "0"; done); 
c=$(echo -e $[$d*$e])"+"$c; 
done; done; 
a=$(echo -e $["${c:0:${#c}-1}"])
echo $a
done

Code: Select all

a="16" # digital number / single digits do not work
for ((z=0; z<100; z++)); do 
b="16"; # should be possible with 2
c=""; for ((y=${#a}-1; y>=0; y--)); do c+=${a:$y:1}; done; a=$c; c=""; for ((x=${#b}-1; x>=0; x--)); do c+=${b:$x:1}; done; b=$c; c=""; # reverse numbers
for ((y=0; y<${#a}; y++)); do for ((x=0; x<${#b}; x++)); do 
d=$[$y+$x]; c+="$d-$[${a:$y:1}*${b:$x:1}] "; # single digit multiplication
done; done; arr=($c); c=""; 
for ((y=0; y<$d+1; y++)); do for ((x=0; x<${#arr[@]}; x++)); do 
[[ $y == $x ]] && continue; 
[[ $y == ${arr[$x]%[-]*} ]] && arr[$y]=$[${arr[$y]#*[-]}+${arr[$x]#*[-]}] && arr[$x]=""; # single result addition
done; c+="${arr[$y]} "; done; arr=(${c##*[-]}); c=""; 
for ((y=0; y<${#arr[@]}; y++)); do 
[[ ${#arr[$y]} == 1 ]] && c+=${arr[$y]}; # single digit position addition
[[ ${#arr[$y]} == 2 ]] && c+=${arr[$y]:1:1} && arr[$y+1]=$[${arr[$y+1]}+${arr[$y]:0:1}]; # double digit position addition
[[ ${#arr[$y]} == 3 ]] && c+=${arr[$y]:2:1} && arr[$y+1]=$[${arr[$y+1]}+${arr[$y]:1:1}] && arr[$y+2]=$[${arr[$y+2]}+${arr[$y]:0:1}]; # triple digit position addition
done; d=""; 
for ((x=${#c}-1; x>=0; x--)); do d+=${c:$x:1}; done; # reverse numbers
a=$d; echo $d # result
done

Code: Select all

#!/bin/bash
a=2   #initial 1st factor 
b=2   #fixed 2nd factor
c=64  #max iteration
for ((i=2;i<=$c;i++)); do
res=
cov=
while [ $a ] ;do
	m=$((${a#${a%?}}*$b+cov))   #multiply last digit of $a with $b and add any remainder to be carried over from previous multiplication
	res=$((m%10))$res           #last digit of m prepended to accumulated result
	cov=$((m/10))               #carry-over for next loop: all digits of m except last. Returns '0' for single digit result.
	a=${a%?}                    #cut last digit
done
a=${cov#0}$res                  #prepend any remaining carry-over value if not 0
echo "Iterations $i:$a"
done

Code: Select all

#!/bin/ash
a=2   #initial 1st factor 
b=2   #fixed 2nd factor
c=64  #max iteration
i=1   #iteration
while [ $i -lt $c ]; do
	res=
	cov=
	i=$((i+1))
	while [ $a ] ;do
		m=$((${a#${a%?}}*$b+cov))   #multiply last digit of $a with $b and add any remainder to be carried over from previous multiplication
		res=$((m%10))$res           #last digit of m prepended to accumulated result
		cov=$((m/10))               #carry-over for next loop: all digits of m except last. Returns '0' for single digit result.
		a=${a%?}                    #cut last digit
	done
	a=${cov#0}$res                  #prepend any remaining carry-over value if not 0
	echo "Iterations $i:$a"
done