Oppiskele Dynamic Allocation of the Array | Dynamic Memory Allocation

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


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#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.

Tehtävä

Swipe to start coding

Imagine you are working as a meteorologist who needs to analyze temperature readings throughout the day.

You will work with pointers and functions that manipulate dynamically allocated arrays of data.

Initialize variables sum to 0, minTemp to the first element of the array, and maxTemp to the first element of the array.
Iterate through the array temps using a for loop with an index i from 0 to hours.
For each element temps[i], add its value to sum.
If temps[i] is less than minTemp, assign temps[i] to minTemp.
If temps[i] is greater than maxTemp, assign temps[i] to maxTemp.
Calculate the average temperature by dividing sum by hours and store it in a variable average.
Print the values of minTemp, maxTemp, and average to the console.

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