Parallel Arrays help

[arooj]

A teacher uses the following table for grades:

Min Grade Max
0 F 299
300 D 349
350 C 399
400 B 449
450 A 500


Construct a program that displays the appropriate grade when the total points a student earned is entered using a parallel array (minimum and grade)
This is what I have so far:

/* Arooj Mohammed	C++	Ch11Ex11

*/

//Ch11.cpp – displays a grade based on the total number of points
//entered by the user

#include <iostream>
#include <string>

using std::cout;
using std::cin;
using std::endl;
using std::string;

int main()
{
	//declare variables and arrays
	int total = 0;
	int minPoints[5] = {0, 300, 350, 400, 450};
	string grade[5] = {"F", "D", "C", "B", "A"};

	//get input
	cout << "Enter total points earned (negative number to end program): ";
	cin >> total; 

	//validate input
	while (total >= 0)
	{			
			int x = 0;
				while (x < 5 && total >= minPoints[x])
				{
					x = x + 1;
				}
			if (x < 5)
			{
				cout << "Grade: " << grade[x] << endl;
			}
			else 
			{
				cout << "Invalid number" << endl;
			}
			cout << "Enter total points earned (negative number to end program): ";
			cin >> total; 

	}	//end while

	return 0;
}  //end of main function 

I keep getting an incorrect output, can someone show me how to correct the program?

Enter total points earned (negative number to end program): 0
Grade: D
Enter total points earned (negative number to end program): 45
Grade: D
Enter total points earned (negative number to end program): 450
Invalid number
Enter total points earned (negative number to end program): 222
Grade: D
Enter total points earned (negative number to end program): 444
Grade: A
Enter total points earned (negative number to end program): 333
Grade: C
Enter total points earned (negative number to end program): -1
Press any key to continue . . .

[CJC0117]

On line 37, try grade[x-1] instead of grade[x].

[Need4Sleep]

You might want to use a for loop for parallel functions like so:

#include <iostream>
#include <string>
/*Min Grade Max
0 F 299
300 D 349
350 C 399
400 B 449
450 A 500
*/
int main()
{
   const std::string Grade[5] = {"F", "D", "C", "B", "A"}; //Grades wont be changing anytime 
   //soon, so i made it constant
   int Min[5] = {0,300,350,400,450};
   int total;
   //you want the loop to run at least once, so you would execute the code, THEN check.
   do{
       std::cout << "***Enter your grade***\n\t";
       std::cin >> total;
       if(total == -1){return 0;} //Makes the program end if user enters -1
        //For loops help with parallel arrays, and are very helpful.
        for(int x = 0; x < 5; x++){ 
            //e.g. -> IF total > 0(min[0]) AND < 300(min[1]) THEN show your grade
            if(total >= Min[x] && total <= Min[x+1]){ 
                //we can use Grade[x] because they are parallel arrays, no need for another for loop
                std::cout << "Your grade is: " << Grade[x] << std::endl;
                std::cout << "Enter another or -1 to quit\n";
                break; //Breaks from the for loop so the while loop can continue
        }
       }

   }while(total >= 0);
   return 0;
}

Please ask questions so you know what this code does, i shouldn't be just giving you the homework, but i was very bored and looking for something to do :).

[ReedTompkins]

Careful -

if(total >= Min[x] && total <= Min[x+1]){

If x = 4 (such as in the case for "A"), Min[x+1] becomes Min[5], which is out of bounds for the array.

That will lead to unpredictable behavior.

[CJC0117]

continuing from what I said before, you'd also have to change line 35 to if(x<6)

[Need4Sleep]

@ReedTompkins
how would you solve that problem? Im interested in how you would go about preventing that.

[arooj]

CJC0117's answers helped me make the program work, thank you all for helping me.