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Now we are ready to write a C function to show a decimal digit on a single 7-segment display.
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In our example, we are going to show a digit whose binary code is represented by the four right-hand 
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side slide switches on the right-hand side 7-segment.
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The algorithm that controls the 7-segment has three steps.
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1- Receiving the decimal digit binary code, 2-Encoding the decimal digit into the corresponding
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7-segment code, 3- Drive the target 7-segment display with this code
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This table shows a decimal digit, its binary and 7-segment codes. A multiplexer can be used 
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to encode the decimal digit. 
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The 10 7-segment codes drive the multiplexer inputs, and the decimal digit feeds the multiplexer control 
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signals as an index to connect proper input code to the output. 
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For example, Let’s consider the digit 6 as the input, 
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then its corresponding code is connected to the output and illuminates the 7-segments.
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Now, let’s write the HLS code for this simple combinational design. 
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A switch-case statement can describe the multiplexer. Each case represents an input in our multiplexer. 
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Notice that in the default case, I’ve assumed that all segments are off. This switch can be encapsulated 
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in a function that receives the decimal digit and returns the 7-segment control and data signals.
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As we just want to enable only one display, 
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the corresponding signal is 0 in the value of the common anode. 
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Finally, we should define the function arguments’ interfaces. As a group of simple wires implements them, 
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then their interface is ap_none. 
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In addition, there is no block-level signalling in this simple example, 
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then the interface attached to the funtion return is ap_ctrl_none.
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Now, we are able to show a decimal digit on a 7-segment. Is there any coding mechanism that facilitates 
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representing a multiple-digit decimal number on a set of seven-segments? 
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To answer this question, in the next lecture, 
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I will explain the Binary Coded Decimal (BCD) technique, which is widely used to represent multiple-digit 
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decimal numbers.
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Also, I show how to convert this coding mechanism into the 7-Segment display code.
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The takeaway message from this lecture is: The C-Code representing a combinational multiplexer can 
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describe the single 7-segment controller.
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Now the quiz question.
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Write the one_digit_seven_segment function explained earlier in this lecture by using the if-else 
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statement instead of switch-case.