Question

Write a C++ program that reads a file consisting of students’ test scores
in the range 0–200. It should then determine the number of students
having scores in each of the following ranges: 0–24, 25–49, 50–74,
75–99, 100–124, 125–149, 150–174, and 175–200. Output the
score ranges and the number of students. (Run your program with the
following input data: 76, 89, 150, 135, 200, 76, 12, 100, 150, 28,
178, 189, 167, 200, 175, 150, 87, 99, 129, 149, 176, 200, 87,
35, 157, 189.)

Answer 1

Thanks for the question, here is the code in C++

Note: Please refer the screenshot for the input file having the scores data. Also, when you run the program make sure you update the filename correctly in the below line -

char * filename ="F:\\scores.txt";

Have included comments so that you can follow the code. Let me know in case you have any questions.

============================================================================

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

// utlility function that accepts a number and returns

// the index in the array where it should be counted

int get_index(int n){
  
   if(n>=200)return 7;
   return n/25;
  
}

// accepts an int array and prints the frequency in the range

void displayHistogram(int range[], int size){
  
   for(int i=0;i<size;i++){
       if(i!=size-1)
       cout<<25*i<<"-"<<i*25+24<<" : "<<range[i]<<endl;
       else
       cout<<25*i<<"-"<<i*25+25<<" : "<<range[i]<<endl;
      
      
   }
}

int main(){

// update the filename of the input file in the below line.
   char * filename ="F:\\scores.txt";
   ifstream infile(filename);
   int range[8]{0};
   if(infile.is_open()){
       int score;
       while(infile>>score){
           range[get_index(score)]+=1;
          
       }
       infile.close();
       displayHistogram(range,8);
      
   }else{
       cout<<"Unable to read data from file: "<<filename<<endl;
   }
}