Question

Set up four different algorithms and flowcharts for calculating a student’s letter grade given the following (do not use straight-through logic):

90-100 = A

80-89 = B

70-79 = C

60-69 = D

below 60 = F

Which of the four solutions would be the best? Justify your answer.

Answer 1

1st algorithm:

1.Start
2.get input marks.
3.if(marks>=90&&marks<=100) make grade='A'
else if(marks>=80&&marks<=89) make grade='B'
else if(marks>=70&&marks<=79) make grade='C'
else if(marks>=60&&marks<=69) make grade='D'
else if(marks<60) make grade='F'
4.print grade.
5.Stop.

1st Program:

#include<stdio.h>
void main()
{
    int marks;
    char grade;
    printf("Enter marks:");
    scanf("%d",&marks);
    a= marks/10;
    if(marks>=90&&marks<=100)
        grade='A';
    else if(marks>=80&&marks<=89)
        grade='B';
    else if(marks>=70&&marks<=79)
        grade='C';
    else if(marks>=60&&marks<=69)
        grade='D';
    else if(marks<60)
        grade='F';
printf("your grade is: %c\n",grade);
}

Output:

Flow Chart:

2nd algorithm:

1.Start
2.get input marks.
3.initialize a = marks/10.
4.if(a==9||a==10) make grade='A';
else if(a==8) make grade='B';
else if(a==7) make grade='C';
else if(a==6) make grade='D';
else if(a<6) make grade='F';
5.print grade.
6.Stop.

2nd Program:
#include<stdio.h>
void main()
{
    int marks;
    int a ;
    printf("Enter marks:");
    scanf("%d",&marks);
   a = marks/10;
   if(a==9||a==10)
        grade='A';
    else if(a==8)
        grade='B';
    else if(a==7)
        grade='C';
    else if(a==6)
        grade='D';
    else if(a<6)
        grade='F';
printf("your grade is: %c\n",grade);
}

flowchart:

3rd algorithm:

1.Start
2.get input marks.
3.switch(marks)
   case 90 ... 100:    grade='A';break;

   case 80 ... 89:       grade='B';break;

   case 70 ... 79:       grade='C';break;

   case 60 ... 69:       grade='D';break;

   case 0 ... 59:       grade='E';break;
4.print grade.
5.Stop.

3rd Program:

#include<stdio.h>
void main()
{
    int marks;
    char grade;
    printf("Enter marks:");
    scanf("%d",&marks);
    switch(marks)
        {
        case 90 ... 100:
            grade='A';
            break;
  
        case 80 ... 89:
            grade='B';
            break;
  
        case 70 ... 79:
            grade='C';
            break;
  
        case 60 ... 69:
            grade='D';
            break;
  
        case 0 ... 59:
            grade='E';
            break;
  
        default:
            printf("wrong marks \n");
  
        }
printf("your grade is: %c\n",grade);
}
4th algorithm:

1.Start
2.get input marks.
3.use ternary operator for assigning grade.
(marks>=90&&marks<=100)?grade='A':((marks>=80&&marks<=89)?grade='B':((marks>=70&&marks<=79)?grade='C':((marks>=60&&marks<=69)?grade='D':((marks<=59)?grade='F':(printf("wrong marks \n"))))))

4.print grade.
5.Stop.

4th Program:

void main()
{
    int marks;
    char grade;
    printf("Enter marks:");
    scanf("%d",&marks);
(marks>=90&&marks<=100)?grade='A':((marks>=80&&marks<=89)?grade='B':((marks>=70&&marks<=79)?grade='C':((marks>=60&&marks<=69)?grade='D':((marks<=59)?grade='F':(printf("wrong marks \n"))))));
printf("your grade is: %c\n",grade);
}

In the above 4 methods used the method using switch statement is the best way to assign grade.