CODEWITHSUNDEEP
bash
Drave
Drave

Reputation: 27

bash- conditional triangle error

my task was to print whether the numbers given signify ISOSCELES,EQUILATERAL, or SCALENE triangle. My code prints only ISOSCELES: Where's the error ?

#!/bin/bash
read a b c
if [ "$a" == "$b" ] && { [ "$b" = "$c" ] && [ "$c" = "$a" ]; }
then
    echo "EQUILATERAL"
exit 1
elif [ "$a" == "$b" ] && { [ "$b" = "$c" ] || [ "$c" = "$a" ]; }
then
    echo "ISOSCELES"
elif ([[ "$a" != "$b" ]] && [[ "$b" != "$c" ]] && [[ "$c" != "$a" ]])
then
    echo "SCALENE"
fi

Upvotes: 0

Views: 591

Answers (6)

MD SARFARAZ
MD SARFARAZ

Reputation: 117

Take the sides of traingles as input using read command.

read a
read b
read c
if (( a == b )) && (( b == c )) && (( c == a )); 
then 
    echo "EQUILATERAL"
elif (( a != b )) && (( b != c )) && (( c != a ));
then 
    echo "SCALENE"
else 
    echo "ISOSCELES"
fi

Upvotes: 0

gboffi
gboffi

Reputation: 25023

  1. you mix == and = in your tests
  2. change the order, first test for EQUILATERAL, then for SCALENE, then you don't need to test for ISOSCELES (quartum non datur;-)

Upvotes: 1

choroba
choroba

Reputation: 241828

You can just count the number of different numbers to get the answer.

#!/bin/bash
read a b c
different=$(printf '%s\n' $a $b $c |
            sort -n                |
            uniq -c                |
            wc -l
         )

case $different in
    (1) echo EQUILITERAL ;;
    (2) echo ISOSCELES   ;;
    (3) echo SCALENE     ;;
esac

You should also verify the triangle inequality at the beginning:

#!/bin/bash
read a b c
sorted=$( printf '%s\n' $a $b $c | sort -n )
ineq=${sorted/$'\n'/+}
ineq=${ineq/$'\n'/>}
(( $ineq )) || exit 1

different=$( uniq -c <<< "$sorted" | wc -l )

case $different in
    (1) echo EQUILITERAL ;;
    (2) echo ISOSCELES   ;;
    (3) echo SCALENE     ;;
esac

Upvotes: 2

chaos
chaos

Reputation: 9282

That a bit simplified:

#!/bin/bash
read a b c
if [ "$a" -eq "$b" ] && [ "$b" -eq "$c" ] && [ "$c" -eq "$a" ];
then
    echo "EQUILATERAL"
    exit 1
elif [ "$a" -ne "$b" ] && [ "$b" -ne "$c" ] && [ "$c" -ne "$a" ];
then
    echo "SCALENE"
else
    echo "ISOSCELES"
fi

I think thats the purposed output:

$ echo "6 6 6" | ./script
EQUILATERAL
$ echo "6 6 5" | ./script
ISOSCELES
$ echo "4 5 6" | ./script
SCALENE

Upvotes: 0

Tom Fenech
Tom Fenech

Reputation: 74595

There's a strange mixture of [, [[, = and == in your script. If you are using bash, I would suggest that you instead use (( )) for all of your numerical comparisons. This creates an arithmetic context, so it also means that you don't need to use $ to refer to your variables:

if (( a == b )) && (( b == c )) && (( c == a )); then echo "equilateral"
elif (( a != b )) && (( b != c )) && (( c != a )); then echo "scalene"
else echo "isoceles"
fi

The separate test for isosceles is unnecessary.

Upvotes: 2

SMA
SMA

Reputation: 37023

Try (use == or -eq for numbers): 

   #!/bin/bash

   read a b c
   if [ "$a" == "$b" ] && { [ "$b" == "$c" ] && [ "$c" == "$a" ]; }
   then
      echo "EQUILATERAL"
  elif ([[ "$a" != "$b" ]] && [[ "$b" != "$c" ]] && [[ "$c" != "$a" ]])
  then
      echo "SCALENE"
  else
     echo "ISOSCELES"
  fi

Upvotes: 0

Related Questions