Question

Homework 1 - Simple Array Handling Write a working C++ program to ask the user for a set of grades which are to be stored in an array in increasing sequence. The user must first provide the number which represents the count of all grades to be provided. For example, if there will be 10 grades, the user is first prompted to provide the number 10. Subsequently, each grade is provided, one at a time. Allow for a maximum of 30 grades in defining the array. When all the grades have been sorted properly, print them all, along with the average. Process the array using a function which is invoked from the main body of the program. The main body asks for the count of grades and then invokes the grade sequencing function. You must write in proper C++ syntax and actually execute the program to ensure it works properly.

Answer 1

/*Whole answer is well commented so please copy whole answer in a .cpp file and execute
Solution Approach:
1. First program will ask user for number of grades, if it is more than 30 program will ask again
2. if grades are less than 30 then it program will create an array of float type, you can change it according to you
3. Then program will pass this array to grades_sequencing(grades) function and function will sort the array in increasing order
using selection sort(please learn about selection sort)
4. After that function will calculate average of grades by sum(grades)/grades.length and display and ans

In function call array is passes as reference so no need to return array from function

Lets understand selection sort:
arr={3,5,2,4}
first iteration: compare 3 with all elements and find index of minimum element and swap them now min is 2
now arr={2,5,3,4}
second iteration : compare 5 with and find index of min element that is 3, swap 3 and 5
now arr={2,3,5,4}
third iteration : compare 5 with and find index of min element that is 4, swap 4 and 5
now arr={2,3,4,5}

Finally array is sorted.

NOTE: If you have any other data type like int so please replace all float with int etc.
*/
//C++ program to find average of grades
#include<iostream>
using namespace std;
//Selection sort function to sequence grades
void selectionSort(float grades[], int n)
{
int i, j, min_ele_idx;

// One by one move boundary of unsorted sub array
for (i = 0; i < n-1; i++)
{
// Find the minimum element in unsorted array means next to i
min_ele_idx = i;
for (j = i+1; j < n; j++)
if (grades[j] < grades[min_ele_idx])
min_ele_idx = j;

// Swap the found minimum element with the ith element
float temp=grades[i];
grades[i]=grades[min_ele_idx];
grades[min_ele_idx]=temp;
}
}
void grades_sequencing(float grades[],int n)
{
//calling selection sort function
selectionSort(grades,n);

float sum=0;
int i;
//now summing all the grades
for(i=0;i<n;i++)
{

sum =sum + grades[i];
}

//calculating average
float average=sum/n;
cout<<"The grades are: " <<endl;
for(i=0;i<n;i++)
cout<<grades[i]<<" ";
cout<<"\n";
cout<<"The Average is: "<<average;
}
int main()
{
//Declaring n size of array
int n;
int i;
//reading n until user enters n less than or equal 30
while(1)
{
cout<<"Please enter number of students: ";
cin>>n;
if(n<=30)
break;
}
//declaring grades array , please change data type of array based on your requirement like float to int or char etc.
float grades[n];

//Now asking user to enter n grades
cout<<"Enter grades of "<<n<<" students: ";
for(i=0;i<n;i++)
cin>>grades[i];

//Calling function to process grades
grades_sequencing(grades,n);
return 0;
}

//Image for input/output

"HAPrograms\C langugelgrades.exe" Please enter number of students: 5 Enter grades of 5 students: 4 3.5 4.8 3.8 3.6 The grades are: 3.5 3.6 3.8 4 4.8 The Average is: 3.94 Process returned (ex execution time 37.072 s Press any key to continue.