c / c-functions
18 mins
C Level 4: Contiguous Memory & Null Strings
Why This Matters: Arrays in C are raw contiguous memory blocks. Strings are character arrays terminated with '\0'.
## Array Indexing & String Buffers
An array allocates elements side-by-side in contiguous memory.
### C Null-Terminated Strings
Strings in C are character arrays that end with the null terminator character `'\0'`.
```c
char str[6] = {'H', 'e', 'l', 'l', 'o', ' '};
// Or string literal equivalent:
char str[] = "Hello";
```
MENTAL MODEL & MEMORY LAYOUT
Memory Array Layout: Index: [0] [1] [2] [3] [4] [5] Value: 'H' 'e' 'l' 'l' 'o' '\0' Address: 0x10 0x11 0x12 0x13 0x14 0x15
COMMON PITFALLS TO AVOID
- Forgetting extra byte for null terminator '\0' in string buffers.
- Accessing array out of bounds (indexing arr[5] on size 5 array).
String Traversal in C
#include <stdio.h>
int main() {
char name[] = "GrowCode";
int len = 0;
while (name[len] != '\0') {
len++;
}
printf("String length: %d\n", len);
return 0;
}Iterates through character buffer until null terminator '\0' is reached.
CONCEPT MASTERY CHECKPOINT
Why is the null character `'\0'` mandatory at the end of C strings?
NEXT RECOMMENDED LESSON
C Level 5: Pointers & Addresses
Challenge: Calculate the sum of array elements `[1, 2, 3, 4, 5]` and print the sum.