Question

Create a c++ program that:

1. Create an input file using notepad ( .txt ). When testing your program using different input files, you must change the filename inside your program otherwise there will be syntax errors.
2. There are a finite number of lines to be read from the data file. But we can’t assume to know how many before the program executes; so, the standard tactic is to keep reading until you find the “End of File” marker.
3. Input date file consists of scores (one per line), might contain no score at all (an empty file) and program does not know how many scores before execution.
4. If file not empty, determine how many valid scores (0 to 100), and how many invalid scores (less than 0 or greater than 100).
5. Take only the valid scores and determine what letter grade and keep track of how many As, Bs, Cs, Ds, and Fs.  

(90 to 100 is an A, 80 to 89 is a B, 70 to 79 is a C, 60 to 69 is a D, 0 to 60 is a F)

6. Output to the screen (not file output) with the followings: the number of valid scores, the number of invalid scores, the highest valid score, the lowest valid score, and the average of the valid scores. Also print out the histogram of the grades (sideway). Look at my output examples
7. If the file is empty, don’t print any statistics at all. If the input file only has invalid scores, just print how many invalid scores and no valid scores, don’t include any statistics.
8. Test your program with difference cases/scenarios.

Answer 1

Code:

#include <fstream>
#include<iostream>
#include <vector>
using namespace std;

void printHistogram(char ch, int num) {
    printf("[%c]",ch);
      for (int j = 0; j < num; ++j) {
        printf("*");
      }
      printf("\n");
}

int main() {
    vector<int>v;
   ifstream is("a.txt");
   int x;
   if ( is.peek() == ifstream::traits_type::eof() )
  {
   // Empty File
  }else{
        while (is >> x){
            //read integer from file
            v.push_back(x);
        }
        int sum=0;
        vector<int>v2;
        int inv, val, A,B,C,D,F;
        for(int i=0; i<v.size(); i++){
            if(v[i]<0 || v[i]>100){
                inv++;
            }else{
                v2.push_back(v[i]);
                val++;
                sum+=v[i];
                if(v[i]<60){
                    F++;
                }else if(v[i]>=60 && v[i]<70){
                    D++;
                }else if(v[i]>=70 && v[i]<80){
                    C++;
                }else if(v[i]>=80 && v[i]<90){
                    B++;
                }else if(v[i]>=90 && v[i]<=100){
                    A++;
                }
            }
        }
        sort(v2.begin(), v2.end());
        if(val==0){
            cout<<"Invalid scores: "<<inv<<endl;
            cout<<"No valid scores"<<endl;
        }else{
            float avg = sum/v2.size();
            cout<<"Valid scores: "<<val<<endl;
            cout<<"Inalid scores: "<<inv<<endl;
            cout<<"Highest valid score: "<<v2[v2.size()-1]<<endl;
            cout<<"Lowest valid score: "<<v2[0]<<endl;
            cout<<"Average valid score: ";
            printf("%.2f\n",avg);
            printHistogram('A',A);
            printHistogram('B',B);
            printHistogram('C',C);
            printHistogram('D',D);
            printHistogram('F',F);
        }
   }
    
    is.close();
        return 0;
}

Output: