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September 28th, 2005, 01:05 AM

Geo.Garnett

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FOR (LOOP) question!!!

when using a for loop how is it possible to use the data collected. for example in this short program how would it be possible to access the entered amounts.

Code:

int main(void)
{
   float testScore = 0;
   cout<<"Test Scores For The Semester\n";
   for(int i = 0; i <= 5; i++)
   {
      cout<<"Score "<<i<<":";
      cin>>testScore;
    }
   return 0;
}

how would I access the five test scores after they are entered. Like, if I wanted to average them all up. I know this is really a

question but for some reason I cant quite grasp it!!

September 28th, 2005, 02:58 AM

Itsacon

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Well, first of all, you'd have to read them all in seperately, right now, each one is overwriting the previous one. Try using an array, like this:

cpp Code:

Original - cpp Code
int main(void) { float testScore[6] = {0}; cout<<"Test Scores For The Semester\n"; for(int i = 0; i <= 5; i++) { cout << "Score " << i << ":"; cin >> testScore[i]; } return 0; }

int main(void)
{
    float testScore[6] = {0};
    cout<<"Test Scores For The Semester\n";
    for(int i = 0; i <= 5; i++)
    {
        cout << "Score " << i << ":";
        cin >> testScore[i];
    }
    return 0;
}

Now, if you want to calculate the average, you have to calculate the total too. You can do this after reading all the variables, (another for loop) but the faster way is to do it in the same loop:

cpp Code:

Original - cpp Code
int main(void) { float sum = 0, testScore[6] = {0}; cout<<"Test Scores For The Semester\n"; for(int i = 0; i <= 5; i++) { cout << "Score " << i << ":"; cin >> testScore[i]; sum += testscore[i]; } cout << "Average: " << (sum / 6.0) << "\n"; return 0; }

int main(void)
{
    float sum = 0, testScore[6] = {0};
    cout<<"Test Scores For The Semester\n";
    for(int i = 0; i <= 5; i++)
    {
        cout << "Score " << i << ":";
        cin >> testScore[i];
        sum += testscore[i];
    }
    cout << "Average: " << (sum / 6.0) << "\n";
    return 0;
}

Hope this helps.

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September 28th, 2005, 11:48 AM

Geo.Garnett

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Thanks for that example, that's a BIG help that's for sure. I guess I don't really understand them mostly because there's so many statements in a small space and although its easy to read through an example in a book and see how that guy would use it, but once its time to do one of your own design that's a little different, ya know, or maybe its just me

But anyways Thx again

Hey but before I quit picking your brain, I got an example that for some reason, stumped the crap out of me, So, here's the question. NOT homework, its a test question out of the book C++ Primer Plus(5th Chapter);

Quote:

Write a program that requests the user to enter two integers. The program should then calculate and report the sum of all the integers between and including the two integers. At this point, assume that the smaller integer is entered first. For Example, if the user entered 2 and 9, the program should report that the sum of all integers from 2 through 9 is 44.

So here's what I got for the answer, and I know its not right, but !!

Code:

int main (void)
{
    int one = 0;
    int two = 0;
    cout<<" Enter The First Number \n";
    cin>>one;
    cin>>two;
    int sum = one + 1;
    for (int i = 1; i <= one%two;i++)
    
    {
        cout<<" Value "<<i<<" : "<<one++ + sum++<<endl;
        }
        
    system("PAUSE");
    return 0;
}

But Im going to try it again with my newly acquired knowledge

September 28th, 2005, 01:34 PM

Itsacon

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Hmm, you've been here long enough to be more than someone who doesn't want to do his homework. Either that or you get a LOT of homework :-)

anyway, here are some solutions to the problem you gave.
The first one, which is clearest:

cpp Code:

Original - cpp Code
#include <stdio.h> int main(void) { // declarations int one, two, i, sum = 0; // read input printf("Give first integer: "); scanf("%d", &one); printf("Give second integer: "); scanf("%d", &two); // calculate sum for(i = one; i <= two; i++) sum = sum + i; // report sum printf("the sum of all integers from %d to %d is %d\n", one, two, sum); // exit return 0; }

#include <stdio.h>
 
int main(void)
{
    // declarations
    int one, two, i, sum = 0;
 
    // read input
    printf("Give first integer: ");
    scanf("%d", &one);
    printf("Give second integer: ");
    scanf("%d", &two);
 
    // calculate sum
    for(i = one; i <= two; i++)
        sum = sum + i;
 
    // report sum
    printf("the sum of all integers from %d to %d is %d\n", one, two, sum);
 
    // exit
    return 0;
}

And the second, which is a lot nastier, and only uses one variable less, but looks cooler because the for-loop is weird :-):

cpp Code:

Original - cpp Code
#include <stdio.h> int main(void) { // declarations int one, two, sum; // read input printf("Give first integer: "); scanf("%d", &one); printf("Give second integer: "); scanf("%d", &two); // start output printf("the sum of all integers from %d to %d is ", one, two); // calculate sum for(sum = 0; one <= two; sum += one++); // finish output printf("%d\n", sum); // exit return 0; }

#include <stdio.h>
 
int main(void)
{
    // declarations
    int one, two, sum;
 
    // read input
    printf("Give first integer: ");
    scanf("%d", &one);
    printf("Give second integer: ");
    scanf("%d", &two);
 
    // start output
    printf("the sum of all integers from %d to %d is ", one, two);
 
    // calculate sum
    for(sum = 0; one <= two; sum += one++);
 
    // finish output
    printf("%d\n", sum);
 
    // exit
    return 0;
}

And finally one that doesn't use for-loops at all, but simple mathematics:

cpp Code:

Original - cpp Code
#include <stdio.h> int main(void) { // declarations int one, two; // read input printf("Give first integer: "); scanf("%d", &one); printf("Give second integer: "); scanf("%d", &two); // print output printf("the sum of all integers from %d to %d is %d\n", one, two, (((1 + two - one) * (one + two)) / 2)); // exit return 0; }

#include <stdio.h>
 
int main(void)
{
    // declarations
    int one, two;
 
    // read input
    printf("Give first integer: ");
    scanf("%d", &one);
    printf("Give second integer: ");
    scanf("%d", &two);
 
    // print output
    printf("the sum of all integers from %d to %d is %d\n", one, two, (((1 + two - one) * (one + two)) / 2));
 
    // exit
    return 0;
}

I love this stuff

September 28th, 2005, 05:01 PM

Geo.Garnett

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TY Itsacon

I appreciate you taking the time to go through that in detail for me, and I was only saying the homework thing because there seemed to be a lot of homework questions floating around lol. Thx Again, this little session helped me tremendously.

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