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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(&currentTime)->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.

Oppgave

Swipe to start coding

Create a dynamic array with a size equivalent to the number of days that have passed.
Free allocated memory.

Løsning

solution.cpp

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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(&currentTime)->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.

Oppgave

Swipe to start coding

Create a dynamic array with a size equivalent to the number of days that have passed.
Free allocated memory.

Løsning

solution.cpp

Bytt til skrivebordet for virkelighetspraksisFortsett der du er med et av alternativene nedenfor

Alt var klart?

Takk for tilbakemeldingene dine!

Sveip for å vise menyen

Dynamic Allocation of the Array

The Limitations of a Static Approach

Løsning

Awesome!

Dynamic Allocation of the Array

The Limitations of a Static Approach

Løsning

Awesome!