Question

Find the errors in following program.

 

//This program uses a switch statement to assign a

// letter grade (A, B, C, D, or F) to numeric test score.

 

 

#include <iostream>

uisng  namespace std;

 

int main()

{

           

            int testScore;

           

            cout<<"Enter your test score and  I will tell you\n";

            cout<<"the letter grade you earned: ";

            cin>>testScore;

 

            switch (testScore)

            {

                        case  (testScore < 60)

                                    cout<<"Your grade is F.\n";

                                    break;

                        case (testScore <70)

                                    cout<<"Your grade is D.\n"

                                    break;

                        case (testScore  <80)

                                    cout<<"Your grade is C.\n";

                                    break;

                        case (testScore < 90)

                                    cout<<"Your grade is B.\n";

                                    break;

                        case (testScore <= 100)

                                    cout<<"Yourgrade is A.\n";

                                    break;

                        default:

                                    cout<<"That score isn't valid\n";

                        return 0;

}

Answer 1

Answer-

Errors in program-

1) switch statement does not accepts conditions.

case (testScore < 60) generates error

2) case must be followed by semicolon(:)

3) before return there must be closing parenthesis of switch ( } )

Switch Statement-It is a multiway branch statement.In switch
statement a variable is tested for different part of code
against a list of values.When value of variable matched with
case that part of program executed.
Syntax-
switch (expression)
{
case 1: // case 1 executed when expression match with
//value of case 1
break;
case 2: // case 2 executed when expression match with
//value of case 2
break;
default: // default will be executed if expression
// doesn't match any cases
}
Conditions for switch statement-
1) Expression should be a constant value or result of
expression provide constant value'
example-
switch(5+3+8)
switch(4*5+9%6)
here both switch statements are valid because expression
derives a constant value.
2) switch statement does not accepts conditions.

Correct Code-

#include <iostream>
using namespace std;
int main()
{
int testScore; // variable declaration
char grade; // variable declaration
cout<<"Enter your test score and i will tell you\n";
cout<<"the letter grade you earned: ";
cin >> testScore;
if(testScore>=90 && testScore<=100) // test score >= 90 and less that 100
{
grade='A';
}
else if(testScore>=80 && testScore<90) // test score >= 80 and <90
{
grade='B';
}
else if(testScore>=70 && testScore<80) // test score >=70 and < 80
{
grade='C';
}
else if(testScore>=60 && testScore<70) // test score >=60 and < 70
{
grade='D';
}
else if(testScore>=0 && testScore<60) // test score >=0 and <60
{
grade='F';
}
  
switch (grade) // switch statement
{
case 'F': // case for < 60
cout<<"Your grade is F.\n";
break;
case 'D': // case for < 70
cout<<"Your grade is D.\n";
break;
case 'C': // case for < 80
cout<<"Your grade is C.\n";
break;
case 'B': // case for <90
cout<<"Your grade is B.\n";
break;
case 'A': // // case for <=100
cout<<"Yourgrade is A.\n";
break;
default: // // case for invalid grade
cout<<"That score isn't valid\n";
}
return 0;
}

Output-