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May 3rd, 2007

average array

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I am trying to write a program that will prompt the user for six grades to be entered (one at a time), read in each grade entered by the user, and store them in an array of six elements. Grades should be on a 0 to 4.0 (inclusive) scale, and the program should accept only grades within that range. I.e. whenever the user enters a grade less than 0 or greater than 4.0, the program will prompt the user to re-enter that grade within the correct range (and do so repeatedly, as long as he/she continues to enter an invalid grade).
The program I wrote doesn't work properly, and I can't figure out what my problem is.

C++ Syntax (Toggle Plain Text)
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
int grade[6];
int i, total = 0;
double average;

cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2); 

for (i = 0; i <= 5; i++){
cout << "Enter grade " << i << " (on a scale of 0.0 to 4.0): ";
cin >> grade[i]; 
{
while(grade[i] < 0.0 || grade[i] > 4.0)
{
cout << "Enter a grade on a scale of 0.0 to 4.0: ";
}
cin >> grade[i];
}
}

for(i = 0; i <= 5; i++)
total = total + grade[i];
average = total/6.0;
}
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
int grade[6];
int i, total = 0;
double average;

cout.setf(ios::fixed);
cout.setf(ios::showpoint);
cout.precision(2); 

for (i = 0; i <= 5; i++){
cout << "Enter grade " << i << " (on a scale of 0.0 to 4.0): ";
cin >> grade[i]; 
{
while(grade[i] < 0.0 || grade[i] > 4.0)
{
cout << "Enter a grade on a scale of 0.0 to 4.0: ";
}
cin >> grade[i];
}
}

for(i = 0; i <= 5; i++)
total = total + grade[i];
average = total/6.0;
}

Last edited by cscgal; May 13th, 2007 at 2:12 pm. Reason: Added code tags

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mathgirl

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May 3rd, 2007

Re: average array

>while(grade[i] < 0.0 || grade[i] > 4.0) Change to while( grade[i] < 0.0 && grade[i] > 4.0)

Aia

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Nearly a Posting Maven

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May 3rd, 2007

Re: average array

Click to Expand / Collapse Quote originally posted by Aia ...

>while(grade[i] < 0.0 || grade[i] > 4.0) Change to while( grade[i] < 0.0 && grade[i] > 4.0)

No, don't, it would always be false. A number can't be less than 0 and greater than 4. Instead, try moving your second line cin>>grad[i]; into the while loop. Right now it just outputs the warning message and loops, since grade[i] never changes

[edit:] And for future reference, please post code between [code] and [/code] tags, which will automatically number them and maintain indentation. Thanks

Last edited by Infarction; May 3rd, 2007 at 8:40 pm.

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May 3rd, 2007

Re: average array

Click to Expand / Collapse Quote originally posted by Infarction ...

No, don't, it would always be false. A number can't be less than 0 and greater than 4. Instead, try moving your second line cin>>grad[i]; into the while loop. Right now it just outputs the warning message and loops, since grade[i] never changes

[edit:] And for future reference, please post code between [code] and [/code] tags, which will automatically number them and maintain indentation. Thanks

My apologies. You are correct. I don't know what I was thinking.

Aia

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Nearly a Posting Maven

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May 3rd, 2007

Re: average array

I moved the cin >> grade[i] into the while loop. I am having a problem because when I enter wrong numbers and it prompts me to enter a new number it includes it as a number in the array and prompts for less numbers.
Thanks!

mathgirl

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May 3rd, 2007

Re: average array

post your new code and ill help you out.

mariocatch

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May 3rd, 2007

Re: average array

C++ Syntax (Toggle Plain Text)
 #include <iostream>
#include <iomanip>
using namespace std;
int main()
{
    int grade[6];
    int i, total = 0;
    double average;
 
    cout.setf(ios::fixed);
    cout.setf(ios::showpoint);
    cout.precision(2);  
 
    for (i = 0; i <= 5; i++){
        cout << "Enter grade " << i << " (on a scale of 0.0 to 4.0): ";
        {
        while(grade[i] < 0.0 || grade[i] > 4.0)
        cin >> grade[i];
        {
   cout << "Enter a grade on a scale of 0.0 to 4.0: ";
        }
        cin >> grade[i];
        }
    }
 
    for(i = 0; i <= 5; i++)
        total = total + grade[i];
    average = total/6.0;
    cout << average << endl;
}
 #include <iostream>
#include <iomanip>
using namespace std;
int main()
{
    int grade[6];
    int i, total = 0;
    double average;
         
    cout.setf(ios::fixed);
    cout.setf(ios::showpoint);
    cout.precision(2);  
         
    for (i = 0; i <= 5; i++){
        cout << "Enter grade " << i << " (on a scale of 0.0 to 4.0): ";
        {
        while(grade[i] < 0.0 || grade[i] > 4.0)
        cin >> grade[i];
        {
   cout << "Enter a grade on a scale of 0.0 to 4.0: ";
        }
        cin >> grade[i];
        }
    }
        
    for(i = 0; i <= 5; i++)
        total = total + grade[i];
    average = total/6.0;
    cout << average << endl;
}

mathgirl

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May 3rd, 2007

Re: average array

Did you even change anything?

Look at it this way: you need to grab the user's input before the while loop, so that you can see if it was invalid or not. Then if it's invalid, the while loop kicks in, which keeps grabbing input until it's valid. Inside the braces { and } of the while loop, you need to have that cin statement.

Here's how it would look:

C++ Syntax (Toggle Plain Text)
    for (i = 0; i <= 5; i++){
            cout << "Enter grade " << i << " (on a scale of 0.0 to 4.0): ";
//        { <- don't need these braces
            cin >> grade[i];
 
            while(grade[i] < 0.0 || grade[i] > 4.0)
            {
                cout << "Enter a grade on a scale of 0.0 to 4.0: ";
                cin >> grade[i];
            }
//        } <- don't need this
    }
    for (i = 0; i <= 5; i++){
            cout << "Enter grade " << i << " (on a scale of 0.0 to 4.0): ";
//        { <- don't need these braces
            cin >> grade[i];
            
            while(grade[i] < 0.0 || grade[i] > 4.0)
            {
                cout << "Enter a grade on a scale of 0.0 to 4.0: ";
                cin >> grade[i];
            }
//        } <- don't need this
    }

Last edited by John A; May 3rd, 2007 at 10:45 pm.

John A

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May 3rd, 2007

Re: average array

why not better do it less complicated:

c Syntax (Toggle Plain Text)
for (i=0;i<=5;i++){
   do{
      cout<<"Enter grade "<<i<<" on a scale from 0.0 to 4.0: ";
      cin>>grade[i];
   }while ((grade[i]<0.00)||(grade[i]>4.00));
}
for (i=0;i<=5;i++){
   do{
      cout<<"Enter grade "<<i<<" on a scale from 0.0 to 4.0: ";
      cin>>grade[i];
   }while ((grade[i]<0.00)||(grade[i]>4.00));
}

Last edited by Nichito; May 3rd, 2007 at 11:34 pm.

Nichito

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May 4th, 2007

Re: average array

do you know wat???

if you want the code to be in between 0 and 4.0,its should be
while(grade>0&&grade<4.0)

also int won't read floating point nos.,

sorry if i'm wrong!!!

try the program now and let me know!!!

Gel

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