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55 lines
1.1 KiB
Markdown
55 lines
1.1 KiB
Markdown
---
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title: "10-intro-to-c-arrays-malloc-free"
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aliases:
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tags:
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- cosc204
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---
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# Arrays
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- must declare with size
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``` c
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uint32_t array[10];
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float matrix[5][6];
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double balance[5] = {1000.0, 2.0, 3.4} //last two elementes will be initalised to zero
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double balance[] = {1000.0, 2.0, 3.4} //size is calculated automatically
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```
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- do not have methods
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- array.size etc
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- not bounds checked
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- can write past the end
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- to know must keep trach yourself or use sentinel value
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- 'H' 'e' 'l' 'l' 'o' '\0' <- sentinel value
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``` c
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//find the length of an array
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size_t strlen(const char *of){
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char *check = of;
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while(*check != '\0')
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check++;
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return check - of;
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}
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```
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# quoted strings
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- "Hello World"
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- must be const - not allowed to change them
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- `const char *hello_world = "hello world"`
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- can use then in place of char arrays
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# Memory
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when we decalre an array we are saying "choose somewhere in memory to put this number of that and call it thing"
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```c
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that thing[this];
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uint_t byte_array[1024];
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```
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- compiler chooses somewhere in memory
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- the name of the array maps to the location
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