In this article, we will discuss how to find out whether the given angles create a valid triangle or not. Here we will take input from the user and, based on the input, we will check whether the angles are equal, less than, or greater than 180 degrees and print the desired result.

Example 

Inputs : 80 60 40
Output : Valid Triangle
 
Inputs : 55 44 30
Output : Invalid Triangle 

A triangle is valid if the sum of all its angles is equal to 180 degrees.

Steps

1. Take the user’s input of three angles as A1, A2, and A3.
   • In Shell Script, “echo” is used to display the text/string on the console.
   • “read” is used to read text from a console.
2. Add all of the angles together and store the result in a variable.
   • Then the input is stored in the sum variable.
3. Then check if the sum of angles is equal to 180 degrees.
   • To check whether the sum is equal to 180 degrees, we use “-eq”, which means equals
4. If true, print valid. Otherwise, the print is invalid.
   • If the condition is satisfied, it prints “Valid Triangle”; else it prints “Invalid Triangle.”
   • In the end, we have used “fi”, which indicates the end of the if loop. 

# Taking input from user
echo "Enter the angles of triangle"
read A1
read A2
read A3

# storing the sum of angles in sum variable
sum=$((A1+A2+A3))

# checking if sum is equal to 180  
if [ $sum -eq 180 ]
  
# if condition is satisfied  
  then
   echo "Valid triangle"

# if condition is not satisfied  
else
  
   echo "Invalid triangle"

# end of if loop
fi

Output:

output

Time complexity: O(1) as constant operations are done

Auxiliary space: O(1)