prog8/examples/pointers/sorting.p8

%import floats
%import strings
%import textio

%zeropage basicsafe

main{
    struct Country {
        str name
        float population        ; millions
        uword area              ; 1000 km^2
    }

    ^^Country[100] countries        ; won't be fully filled
    ubyte num_countries

    sub start() {
        txt.lowercase()
        ; because pointer array initialization is not supported yet, we have to add the countries in separate statements for now
        add(Country("Indonesia", 285.72, 1904))
        add(Country("Congo", 112.83, 2344))
        add(Country("Vietnam", 101.60, 331))
        add(Country("United States", 347.28, 9372))
        add(Country("Iran", 92.42, 1648))
        add(Country("Turkey", 87.69, 783))
        add(Country("Brazil", 212.81, 8515))
        add(Country("Bangladesh", 175.69, 147))
        add(Country("Germany", 84.08, 357))
        add(Country("Japan", 123.10, 377))
        add(Country("India", 1463.87, 3287))
        add(Country("China", 1416.10, 9596))
        add(Country("Philippines", 116.79, 300))
        add(Country("Russia", 143.99, 17098))
        add(Country("Pakistan", 255.22, 881))
        add(Country("Nigeria", 237.53, 923))
        add(Country("Ethiopia", 135.47, 1104))
        add(Country("Mexico", 131.95, 1964))
        add(Country("Thailand", 71.62, 513))
        add(Country("Egypt", 118.37, 1002))

        txt.print("UNSORTED:\n")
        dump()

        sort_by_population()
        txt.print("\nSORTED BY POPULATION:\n")
        dump()

        sort_by_area()
        txt.print("\nSORTED BY AREA:\n")
        dump()

        sort_by_name()
        txt.print("\nSORTED BY NAME:\n")
        dump()
    }

    sub sort_by_name() {
        ; stupid slow bubble sort
        ubyte n = num_countries
        do {
            ubyte newn=0
            ubyte i
            for i in 1 to n-1 {
                if strings.compare(countries[i-1].name, countries[i].name) > 0 {
                    swap(i, i-1)
                    newn = i
                }
            }
            n = newn
        } until n<=1
    }

    sub sort_by_population() {
        ; stupid slow bubble sort
        ubyte n = num_countries
        do {
            ubyte newn=0
            ubyte i
            for i in 1 to n-1 {
                if countries[i-1].population < countries[i].population {
                    swap(i, i-1)
                    newn = i
                }
            }
            n = newn
        } until n<=1
    }

    sub sort_by_area() {
        ; stupid slow bubble sort
        ubyte n = num_countries
        do {
            ubyte newn=0
            ubyte i
            for i in 1 to n-1 {
                if countries[i-1].area < countries[i].area {
                    swap(i, i-1)
                    newn = i
                }
            }
            n = newn
        } until n<=1
    }

    sub swap(ubyte i, ubyte j) {
        ^^Country temp = countries[i]
        countries[i] = countries[j]
        countries[j] = temp
    }

    sub dump() {
        txt.print("name           pop.(millions)  area (1000 km^2)\n")
        txt.print("-------------- --------------- ----------------\n")

        ^^Country c
        for c in countries {
            if c==0
                break
            txt.print(c.name)
            txt.column(15)
            txt.print_f(c.population)
            txt.column(31)
            txt.print_uw(c.area)
            txt.nl()
        }
    }

    sub add(^^Country c) {
        countries[num_countries] = c
        num_countries++
    }
}