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This page introduces the basics of programming using C/C++. |
What is programming
Programming is the process of creating complex behaviour by giving simple instructions to a computer. It is the art of creating a program – a sequence of instruction which the computer should execute to achieve a specific task.
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The code is written in, compiled and finally downloaded in the micro-controller using an Integrated Development Environment. Although the CRC Robotics Competition participants are free to use whatever Arduino compatible IDE, we strongly recommend (and only support) the official desktop-based Arduino IDE.
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In Arduino IDE, compiling is known as verifying and code is written in |
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Computers can natively only perform operations on some data types. These are integer and floating point (float) numbers. Those are called primitives. Integers are further divided in two classes, signed and unsigned. Signed numbers can represent negative as well as positive integers (signed = with a sign, get it?), while unsigned numbers can’t.
Here is a summary chart:
Primitive | Can it represent decimal numbers (e.g. 0.1)? | Can it represent negative numbers (e.g. -2)? |
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Floats | Yes | Yes |
Signed integers | No | Yes |
Unsigned integers | No | No |
While it could be tempting to always use floats, you should always strive to use the type that provides the least while providing what you need. By removing some possibilities, you can avoid small mistakes because of inattention. Computers are also generally faster with integers than with floats.
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In a more understandable format:
Type | Also known as in Arduino | Negatives? | Size (bit) | Minimum | Maximum |
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uint8_t | unsigned char or byte | No | 8 | 0 | 28 - 1 (255) |
int8_t | char | Yes | 8 | -27 (-128) | 27 - 1 (127) |
uint16_t | unsigned int or word | No | 16 | 0 | 216 - 1 (65 535) |
int16_t | int | Yes | 16 | -215 (-32 768) | 215 - 1 (32 767) |
uint32_t | unsigned long | No | 32 | 0 | 232 - 1 (4 294 967 295) |
int32_t | long | Yes | 32 | -231 (-2 147 483 648) | 231 - 1 (2 147 483 647) |
uint64_t | unsigned long long | No | 64 | 0 | 264 - 1 (3.68935 × 1019) |
int64_t | long long | Yes | 64 | -263 (-9.22337 × 1018) | 263 - 1 (9.22337 × 1018) |
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When starting, you can use the “Also known as in Arduino” nomenclature, but you should try to understand and use the official integer nomenclature. In the official nomenclature, the size of every int type is explicitely defined and the same on every platform, whereas an “int” might be 16bit on a micro-controller model and 32bit on another one. Using this nomenclature is a nice habit since it makes your code more portable; meaning that it will have the same execution characteristic on different platforms. |
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