# Interactive Calculator

```#!/bin/bash

#Author: Rajesh
#Veresion: 1.2 (Version 1.1 did not have square and square root options)

# This script will perform simple arithematic operations including decimal numbers.

echo -e "Choose Option: \n 1: For Addition, Subtraction, Multiplication and Division of TWO numbers. \n 2: For Square and Square Root of A number"

read OPTION

if [ "\$OPTION" -eq 1 ]                 # Start of the outer loop. The main LOOP.

then

echo "Enter First Number. Decimals are accepted"

read FIRST_NUM

sleep 1

echo "Enter Second Number. Decimals are accepted"

read SECOND_NUM

sleep 2

echo -e "What operation would you like to perform.\n Enter A OR a for Addition, S OR s for Substraction, M OR m for multiplication,  D OR d for division."

read INPUT

sleep 2

CHOICE=\${INPUT^^}        # This converts the input to uppercase so you only have to compare one letter.

if [ "\$CHOICE" = "A" ]    # Start of the first inner loop

then

SUM=\$(echo "scale=2; \$FIRST_NUM+\$SECOND_NUM" | bc)

#Since bash is weak with floating numbers, tools like bc have to be used to get decimal values.#Hopefully its installed on your system. "yum install -y  bc" in-case you were wondering.

echo -e "The sum of numbers you entered is:\n \$SUM"

elif [ "\$CHOICE" = "S" ]

then

SUB=\$(echo "scale=2; \$FIRST_NUM-\$SECOND_NUM" | bc)

echo -e "The difference of numbers you entered is:\n \$SUB"

elif [ "\$CHOICE" = "M" ]

then

MUL=\$(echo "scale=2; \$FIRST_NUM*\$SECOND_NUM" | bc)

echo -e "The product of numbers you entered is:\n \$MUL"

elif [ "\$CHOICE" = "D" ]

then

DIV=\$(echo "scale=2; \$FIRST_NUM/\$SECOND_NUM" | bc)

echo -e "The division of numbers you entered is:\n \$DIV"

else

echo -e "You did not choose a right option.\n `sleep 1` Exiting the program ......."

sleep 1

fi                        # The first inner loop finishes here

elif [ "\$OPTION" = 2 ]          # The outer loop continues

then

echo "Enter SQ or sq for Square, SR or sr for Square Root"

read INPUT2

sleep 1

echo "Enter a number"

read NUM

CHOICE2=\${INPUT2^^}

if [ "\$CHOICE2" = "SQ" ]      # Start of the second inner loop

then

SQUARE=\$(echo "scale=2; \$NUM*\$NUM" | bc)

echo -e "The square of the number you entered is:\n \$SQUARE"

elif [ "\$CHOICE2" = "SR" ]

then

SQROOT=\$(echo "scale=2; sqrt(\$NUM)" | bc)

echo -e "The square root of the number you entered is:\n \$SQROOT"

else

echo -e "You did not choose a right option.\n `sleep 1` Exiting the program ......."

fi                   # The second inner loop finishes here

else

echo -e "You did not choose a right option.\n `sleep 1` Exiting the program ......."

fi                      # The main loop finally ends```

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