Dynamic Allocation of the Array
Before we explore why dynamic allocation is necessary, let's quickly recap the characteristics of static and dynamic arrays:
- Fixed Size: Once declared, the size of a static array is fixed and cannot be changed during runtime;
- Memory Allocation at Compile Time: The memory required for a static array is allocated at compile time.
- Resizable: Dynamic arrays allow for resizing during runtime, providing flexibility to adapt to changing program requirements;
- Memory Allocation at Runtime: Memory for dynamic arrays is allocated during program execution.
The Limitations of a Static Approach
Consider the program that prompts the user to input performance scores for each day that has passed in current month.
Unfortunately, we can't achieve this using a static array:
main.cpp
12345678910#include <iostream> #include <ctime> int main() { std::time_t currentTime = std::time(nullptr); int day_passed = std::localtime(¤tTime)->tm_mday; int arr[day_passed]; std::cout << day_passed << std::endl; }
Note
This will generate a compilation error because day_passed is not a constant expression it depends on the runtime value of the current day of the month.
So instead of static array we have to use a dynamic allocated array.
Swipe to start coding
- Create a dynamic array with a size equivalent to the number of days that have passed.
- Free allocated memory.
Lösning
solution.cpp
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Before we explore why dynamic allocation is necessary, let's quickly recap the characteristics of static and dynamic arrays:
- Fixed Size: Once declared, the size of a static array is fixed and cannot be changed during runtime;
- Memory Allocation at Compile Time: The memory required for a static array is allocated at compile time.
- Resizable: Dynamic arrays allow for resizing during runtime, providing flexibility to adapt to changing program requirements;
- Memory Allocation at Runtime: Memory for dynamic arrays is allocated during program execution.
The Limitations of a Static Approach
Consider the program that prompts the user to input performance scores for each day that has passed in current month.
Unfortunately, we can't achieve this using a static array:
main.cpp
12345678910#include <iostream> #include <ctime> int main() { std::time_t currentTime = std::time(nullptr); int day_passed = std::localtime(¤tTime)->tm_mday; int arr[day_passed]; std::cout << day_passed << std::endl; }
Note
This will generate a compilation error because day_passed is not a constant expression it depends on the runtime value of the current day of the month.
So instead of static array we have to use a dynamic allocated array.
Swipe to start coding
- Create a dynamic array with a size equivalent to the number of days that have passed.
- Free allocated memory.
Lösning
solution.cpp
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Completion rate improved to 5.88single
