Arrays with user-input

[cisintraining]

Hi guys! I have to write a code for a class project.

I need to calculate the highest score, the lowest score, and the average score. How do I do that?

Not looking for anyone to write the code for me, just maybe some tips on what to do.

#include <iostream>

using namespace std;

int main()
{
	int class_size;
	
	cout << "How many students are in your class? ";
	cin >> class_size;
	cout << endl;
	
	int exam_score[class_size];
	
	for(int i = 1; i <= class_size; i++)
	{
	cout << "What is the final score for student " << i << ": ";
	cin >> exam_score[i];
	}

}

[Ganado]

Let's say you have a list of items {4, 2, 5, 3}.

The average is the easiest part, you have to use a for loop to sum each variable, and then divide by 4.0 (the number of items in your list) to get the average. have a variable called "sum" that you use to accumulate the total before you divide by class_size.
sum = 0
sum += 4
sum += 2
sum += 5
sum += 3
sum / 4.0 == the average

With min and max, declare two variables where you store what the min and max of the array are "so far".

For example, with the above array, you iterate through it with a for loop, and you need to check if the current element is less greater than the element you have stored as the max (so far). If the current element is greater than what you have as the maximum, that element becomes the new maximum.

int max = -1000; // start off as an impossibly low number

check 4 --> is 4 greater than -1000? Yes, 4 is now the max number.
check 2 --> is 2 greater than 4? No, 4 is still the max.
check 5 --> is 5 greater than 4? Yes, 5 is now the max number.
check 1 --> is 1 greater than 5? No, 5 is still the max number

et viola, 5 is your max.
Do almost the same thing with min.

Note that arrays start at index 0, not 1.

Also: Variable-length arrays are not allowed in C++, an array size must be a compile-time constant to be used in that manner (class_size). You either have to create a dynamic array or an std::vector.

#include <iostream>
#include <vector> 

using namespace std;

int main()
{
	int class_size;
	
	cout << "How many students are in your class? ";
	cin >> class_size;
	cout << endl;
	
	std::vector<int> exam_score(class_size);
	
	for(int i = 0; i < class_size; i++)
	{
		cout << "What is the final score for student " << i+1 << ": ";
		cin >> exam_score[i];
	}
}

[ballinlinda]

double average = 0.0;
double min = exam_score[0];
double max = exam_score[0];


if(min > exam_score[i])
//assign new number to min
if(max < exam_score[i])
//assign new number to max

av += v[i];

outside of loop
av /= class_size;


//use exam_score.size()
//not class_size
//because only for arrays you would use class_size since array size cannot change
//vector size can be changed if you erase a exam score
//so lets say you erase the last number
//so the loop counter would point to a unknown memory location, you will get a out of range error

//please use the vector page on cplusplus you will see a lot of useful vector member fuctions

//to input into a vector
//use exam_score.push_back(i);
//[ ] operator is a way to access that cell