Resistor Color Duo

Instructions

If you want to build something using a Raspberry Pi, you'll probably use resistors. For this exercise, you need to know two things about them:

• Each resistor has a resistance value.
• Resistors are small - so small in fact that if you printed the resistance value on them, it would be hard to read.

To get around this problem, manufacturers print color-coded bands onto the resistors to denote their resistance values. Each band has a position and a numeric value.

The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single number. For example, if they printed a brown band (value 1) followed by a green band (value 5), it would translate to the number 15.

In this exercise you are going to create a helpful program so that you don't have to remember the values of the bands. The program will take color names as input and output a two digit number, even if the input is more than two colors!

The band colors are encoded as follows:

• black: 0
• brown: 1
• red: 2
• orange: 3
• yellow: 4
• green: 5
• blue: 6
• violet: 7
• grey: 8
• white: 9

From the example above: brown-green should return 15, and brown-green-violet should return 15 too, ignoring the third color.

Reserved Addresses

The buffer for the first string uses bytes 1024-2047 of linear memory. The buffer for the second string uses bytes 2048-3071 of linear memory.

You should not have to modify these buffers or allocate additional memory.

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Source

Maud de Vries, Erik Schierboom