Question

(JAVA) Write a program that maintains student test scores in a two-dimesnional array, with the students identified by rows and test scores identified by columns. Ask the user for the number of students and for the number of tests (which will be the size of the two-dimensional array). Populate the array with user input (with numbers in {0, 100} for test scores). Assume that a score >= 60 is a pass for the below. Then, write methods for:

Computing the number of tests that each student passed

Computing the number of students passed for each test

The methods should accept a two-dimensional array as one argument and a specific student number (for (a)) or a specific test number (for (b)) as the other argument. The methods should return the relevant counts. Call the above methods (from main) by passing the two-dimensional array that contains the test scores, for each student (for (a)) and then for each test (for (b)). Print the counts. Expert Answer

Answer 1

import java.util.Scanner;

public class StudentTestScores {
  
public static void main(String[] args)
{
Scanner sc = new Scanner(System.in);
System.out.print("How many students: ");
int nStudents = Integer.parseInt(sc.nextLine().trim());
System.out.print("How many test scores for each student: ");
int nTests = Integer.parseInt(sc.nextLine().trim());
  
int studentsTests[][] = new int[nStudents][nTests];
  
System.out.println("\nEnter the test scores for each student:");
for(int i = 0; i < nStudents; i++)
{
System.out.println("Student " + (i + 1) + ": ");
for(int j = 0; j < nTests; j++)
{
studentsTests[i][j] = Integer.parseInt(sc.nextLine().trim());
}
System.out.println();
}
System.out.println();
  
// METHOD 1
int studentNumber = 1; // sample test
studentNumber--;
if(studentNumber < 0)
studentNumber = 0;
  
int testsEachStudentPassed = NTestsEachStudentPassed(studentsTests, studentNumber);
System.out.println("Number of tests Student " + (studentNumber + 1) + " passed = " + testsEachStudentPassed);
  
// METHOD 2
int testNumber = 2; // sample test
testNumber--;
if(testNumber < 0)
testNumber = 0;
  
int studentsEachTestPassed = NStudentsEachTestPassed(studentsTests, testNumber);
System.out.println("Number of students passed Test " + (testNumber + 1) + " = " + studentsEachTestPassed);
}
  
// this method takes the 2-d array and a student number as input
// and returns the number of tests the student passed for
private static int NTestsEachStudentPassed(int students[][], int studentNumber)
{
int count = 0;
  
if(studentNumber < 0 || studentNumber > students.length)
System.out.println("\nInvalid student number!");
else
{
for(int i = 0; i < students[studentNumber].length; i++)
{
if(students[studentNumber][i] >= 60)
count++;
}
}
  
return count;
}
  
// this method takes the 2-d array and a test number as input
// and returns the number of students passed for that test number
private static int NStudentsEachTestPassed(int students[][], int testNumber)
{
int count = 0;
  
if(testNumber < 0 || testNumber > students[0].length)
System.out.println("\nInvalid test number!");
else
{
for(int i = 0; i < students.length; i++)
{
if(students[i][testNumber] >= 60)
count++;
}
}
  
return count;
}
}

********************************************************************* SCREENSHOT ******************************************************

run: How many students: 3 How many test scores for each student: 5 Enter the test scores for each student: Student 1: Student 2: 58 Student 3: 91 96 89 100 100 Number of tests Student 1 passed = 2 Number of students passed Test 2 = 1 BUILD SUCCESSFUL (total time: 45 seconds)