Print Histogram

      

 

This is the C++ program example to print a histogram to represent a set of data input by user. See the example program input and output :



 Coding:

/*
C++ code to print histogram

*/
#include<iostream>
#include<conio.h>
#include<iomanip>

using namespace std;

int findmax(int vals[],int n){
    int max=vals[0];
    for(int i=0;i<n;i++)
        if(max<vals[i]) max=vals[i];
    return max;
}

int main()
{

   int n,fsize;
   cout<<"Enter number of data points:";
   cin>>n;
   int vals[n];
   for(int i=0;i<n;i++){
        cout<<"Value"<<i+1<<":";
        cin>>vals[i]; //intialize data
  }
   int m=findmax(vals,n); //find max value of data points
   if(m>n) fsize=m+1;
   else fsize=n;
   int freq[fsize]; //declare frequency array with an appropriate size
   //The size of frequency array can be the size of the vals array
   //or the max value of the vals array items plus 1

    for(int i=0;i<fsize;i++) //initialize frequency array
          freq[i]=0;

   //compute frequencies
   for(int i=0;i<n;i++)
       freq[vals[i]]++;

   //print histogram
    cout<<"\n....Histogram....\n\n";
    for(int i=0;i<fsize;i++){
       cout<<left;
       cout<<setw(5)<<i;
       cout<<setw(5)<<freq[i];
       for(int j=1;j<=freq[i];j++) cout<<"*";
       cout<<"\n";
   }


   system("PAUSE");
   return 0;


}