Kotlin Simple Calculator with 40 lines

Code

Usage

val str = "5 + 5"
print(eval(str)) //10

With exception handling

try {
    println(eval(str))
} catch (e: IllegalExpressionException) {
    println("Error '${e.message}' index = ${e.index}")
}

Features

• + addition

  5 + 5 = 10

• - substration

  5 - 5 = 0

• * multiplication

  5 * 5 = 25

• * division

  5 / 5 = 1

• * sign support

  +5 - -5 = 10

• floating number support

  10.5 - 0.5 = 10

• priority support

  5 + 5 * 5 = 30

• priority bracket support

  5 * (5 + 5) = 50

• spacing support

  5 * ( 5+5) = 50

• wrong expression handled

  5+++5 -> IllegalExpressionException(index=1, "Invalid number")

• Calculation with single string iteration