bash for loop

#!/bin/bash
for (( c=1; c<=5; c++ ))
do  
   echo "Welcome $c times"
done
years=(2018 2019)
days=(74 274)

for year in "${years[@]}"; do
    for day in $(seq -w ${days[0]} ${days[1]}); do
               echo $year
               echo $day
    done
donewhile [ <some test> ]
do
<commands>
donefor VARIABLE in 1 2 3 4 5 .. N
do
	command1
	command2
	commandN
donefor VARIABLE in file1 file2 file3
do
	command1 on $VARIABLE
	command2
	commandN
done