Coding using vector

[husnamasri]

Hi,i'm still new for c++ programming..can anyone help me with this coding..this is the question..

Write C++ program that reads student scores, finds the best score, and then assign grades based on the following scheme:

Grade is A if score is >= best – 10; Grade is D if score >= 40;
Grade is B if score is >= best – 20; Grade is F otherwise.
Grade is C if score is >= best – 30;

The program prompts the user to enter the total number of students, then prompts the user to enter all of the scores, and concludes by displaying the grades. Below shows a sample run:

Enter the number of students: 4
Enter 4 scores: 40 55 70 58
Student 1 score is 40 and grade is C
Student 2 score is 55 and grade is C
Student 2 score is 55 and grade is A
Student 2 score is 55 and grade is B

This is the code so far:

#include <iostream>
#include <vector>

using namespace std;

int main() {
double num, best;
vector <int> score;
vector <char> grade;
cout<<"Enter the number of students: "; cin>>num;
cout<<"Enter "<<num<<" scores: ";

for (int i = 0; i < num; i++) {
cin>>score[i];}

best = score[0];
for (int i = 0; i < num; i++) {
if (score[i] > best) best = score[i];}

for (int i = 0; i < num; i++) {
if (score[i] >= -10) grade[i] = 'A';
else if (score[i] >= -20) grade[i] = 'B';
else if (score[i] >= -30) grade[i] = 'C';
else if (score[i] >= -40) grade[i] = 'D';
else grade[i] = 'F';}

for (int i = 0; i < num; i++) {
cout<<"Student "<<i + 1<<" score is "<<score[i]<<" and grade is "<<grade[i]<<endl;
}

return 0;
}

[jlb]

Look at the following snippet.
if (score[i] >= -10) grade[i] = 'A';
Does this code fulfill the assignment specifications?

Grade is A if score is >= best – 10;

Please use code tags when posting code, and you also need to ask a specific question in the body of your post.

[husnamasri]

jlb, i donn't exactly understand what you're trying to say..can u explain it..

[Enoizat]

This is a shorter version of your code:

// Write C++ program that reads student scores, finds the best score, and then 
// assign grades based on the following scheme:
// Grade is A if score is >= best – 10; Grade is D if score >= 40;
// Grade is B if score is >= best – 20; Grade is F otherwise.
// Grade is C if score is >= best – 30;
// The program prompts the user to enter the total number of students, then 
// prompts the user to enter all of the scores, and concludes by displaying 
// the grades. Below shows a sample run:
// Enter the number of students: 4
// Enter 4 scores: 40 55 70 58
// Student 1 score is 40 and grade is C
// Student 2 score is 55 and grade is C
// Student 2 score is 55 and grade is A
// Student 2 score is 55 and grade is B
#include <iostream>
#include <vector>

void waitForEnter();

int main()
{ 
    std::cout<<"Enter the number of students: ";
    int num = 0;
    std::cin >> num;

    std::cout << "Enter " << num << " scores: ";
    std::vector <int> scores;
    int best = 0;
    for (int i = 0; i < num; i++) {
        int tmp = 0;
        std::cin >> tmp;
        scores.push_back(tmp);
        if(tmp > best) { best = tmp; }
    }

    for (int i = 0; i < num; i++) {
        std::cout << "Student " << i + 1 << " score is " << scores.at(i)
                  <<" and grade is ";
        if      (scores.at(i) >= -10) { std::cout << "A\n"; }
        else if (scores.at(i) >= -20) { std::cout << "B\n"; }
        else if (scores.at(i) >= -30) { std::cout << "C\n"; }
        else if (scores.at(i) >= -40) { std::cout << "D\n"; }
        else                          { std::cout << "F\n"; }

    }
    return 0;
}

I think what jlb is telling you is you aren't respecting the assignment specifications when you evaluate the grades starting from the scores. You're missing a point; just read them more carefully.

[jlb]

i donn't exactly understand what you're trying to say..can u explain it..

In your if statements where are you do the computations?

// Grade is A if score is >= best – 10; Grade is D if score >= 40;
// Grade is B if score is >= best – 20; Grade is F otherwise.
// Grade is C if score is >= best – 30;

And you still haven't actually asked a question. Maybe "u explain it", the problem that is.

[lastchance]

#include <iostream>
#include <valarray>
using namespace std;

int main()
{
   char grade[] = { 'A', 'B', 'C', 'D', 'F' };
   int num;
   cout << "How many students? ";
   cin >> num;
   valarray<int> score( num ), rank( num );

   cout << "Enter " << num << " scores\n";
   for ( int i = 0; i < num; i++ ) cin >> score[i];

   int best = score.max();
   rank = ( best - score - 1 ) / 10;
   for ( int &r : rank ) if ( r > 4 ) r = 4;

   for ( int i = 0; i < num; i++ ) cout << "Student: " << i + 1 << "   score: " << score[i] << "   grade: " << grade[rank[i]] << '\n';
}

You are ignoring "best", your condition for grade 'D' is inconsistent (I'm guessing in the code above) and your model answer doesn't make sense.

Please clarify.