// Demostrate operator overloading. class Demo: CustomStringConvertible { var value: Int // Default constructor initializing with zero. init() { value = 0 } // init // Integer value constructor initializing with // number. init(initializeWith v: Int) { value = v } // init // Copy constructor initializing with value of demo. init(i: Demo) { value = i.value } // init // Return the value as our class' string. var description: String { return "\(value)" } // description // Binary equal comparison with integer. static func ==(d: Demo, v: Int) -> Bool { return d.value == v } // == // Binary equal comparison with class. static func ==(l: Demo, r: Demo) -> Bool { return l.value == r.value } // == // Binary not equal comparison with integer. static func !=(d: Demo, v: Int) -> Bool { return d.value != v } // != // Binary not equal comparison with class. static func !=(l: Demo, r: Demo) -> Bool { return l.value != r.value } // != // Binary less equal comparison with integer. static func <=(d: Demo, v: Int) -> Bool { return d.value <= v } // <= // Binary less equal comparison with class. static func <=(l: Demo, r: Demo) -> Bool { return l.value <= r.value } // <= // Binary greater equal comparison with integer. static func >=(d: Demo, v: Int) -> Bool { return d.value >= v } // >= // Binary greater equal comparison with class. static func >=(l: Demo, r: Demo) -> Bool { return l.value >= r.value } // >= // Binary less comparison with integer. static func <(d: Demo, v: Int) -> Bool { return d.value < v } // < // Binary less comparison with class. static func <(l: Demo, r: Demo) -> Bool { return l.value < r.value } // < // Binary greater comparison with integer. static func >(d: Demo, v: Int) -> Bool { return d.value > v } // > // Binary greater comparison with class. static func >(l: Demo, r: Demo) -> Bool { return l.value > r.value } // > // Unary plus operator. static prefix func +(d: Demo) -> Demo { return Demo(i: d) } // + // Binary plus operator with integer. static func +(l: Demo, r: Int) -> Demo { return Demo(initializeWith: l.value+r) } // + // Binary plus operator with class. static func +(l: Demo, r: Demo) -> Demo { return Demo(initializeWith: l.value+r.value) } // + // Binary plus equal operator with integer. static func +=(l: inout Demo, r: Int) { l.value += r } // += // Binary plus equal operator with class. static func +=(l: inout Demo, r: Demo) { l.value += r.value } // += // Preincrement operator to increment and return. static prefix func ++(d: inout Demo) -> Demo { d.value += 1 return d } // ++ // Postincrement operator to return copy of current // before incrementing. static postfix func ++(d: inout Demo) -> Demo { var r = Demo(initializeWith: d.value) d.value += 1 return r } // ++ // Unary minus operator. static prefix func -(d: Demo) -> Demo { return Demo(initializeWith: -d.value) } // - // Binary minus operator with integer. static func -(l: Demo, r: Int) -> Demo { return Demo(initializeWith: l.value-r) } // - // Binary minus operator with class. static func -(l: Demo, r: Demo) -> Demo { return Demo(initializeWith: l.value-r.value) } // - // Binary minus equal operator with integer. static func -=(l: inout Demo, r: Int) { l.value -= r } // -= // Binary minus equal operator with class. static func -=(l: inout Demo, r: Demo) { l.value -= r.value } // -= // Predecrement operator to decrement and return. static prefix func --(d: inout Demo) -> Demo { d.value -= 1 return d } // -- // Postdecrement operator to return copy of current // before decrementing. static postfix func --(d: inout Demo) -> Demo { var r = Demo(initializeWith: d.value) d.value -= 1 return r } // -- // Binary asterisk operator with integer. static func *(l: Demo, r: Int) -> Demo { return Demo(initializeWith: l.value*r) } // * // Binary asterisk operator with class. static func *(l: Demo, r: Demo) -> Demo { return Demo(initializeWith: l.value*r.value) } // * // Binary asterisk equal operator with integer. static func *=(l: inout Demo, r: Int) { l.value *= r } // *= // Binary asterisk equal operator with class. static func *=(l: inout Demo, r: Demo) { l.value *= r.value } // *= // Binary slash operator with integer. static func /(l: Demo, r: Int) -> Demo { return Demo(initializeWith: l.value/r) } // / // Binary slash operator with class. static func /(l: Demo, r: Demo) -> Demo { return Demo(initializeWith: l.value/r.value) } // / // Binary slash equal operator with integer. static func /=(l: inout Demo, r: Int) { l.value /= r } // /= // Binary slash equal operator with class. static func /=(l: inout Demo, r: Demo) { l.value /= r.value } // /= // Binary percent operator with integer. static func %(l: Demo, r: Int) -> Demo { return Demo(initializeWith: l.value%r) } // % // Binary percent operator with class. static func %(l: Demo, r: Demo) -> Demo { return Demo(initializeWith: l.value%r.value) } // % // Binary percent equal operator with integer. static func %=(l: inout Demo, r: Int) { l.value %= r } // %= // Binary percent equal operator with class. static func %=(l: inout Demo, r: Demo) { l.value %= r.value } // %= // Return the current value. func toInt() -> Int { return value } // toInt } // Demo let five = +Demo(initializeWith: 5) assert(five == 5, "Not equal") print(five) // 5 let six = five + 1 assert(six == 6, "Not equal") print(six) // 6 var play = six / five assert(play == 1, "Not equal") print(play) // 1 var n = 1 + five.toInt() assert(n == 6, "Not equal") print(n) // 6 play *= n assert(play == 6, "Not equal") print(play) // 6 if (-play >= five) { // false n = 1 play++ } else { n = 0 --play } // if assert(n == 0, "Not equal") print(n) // 0 assert(play == 5, "Not equal") print(play) // 5 play %= 2; assert(play == 1, "Not equal") print(play) // 1 play = Demo(initializeWith: n) + five + play - six; assert(play == 0, "Not equal") print(play) // 0

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