Count Total Each Alphabet of a String in Linked List with C++.

#include <iostream>

using namespace std;

struct list

{

    char alphabet;

    int count;

    struct list *next;

};

typedef struct list node;

node *head=NULL;

void print_node()

{

    node *temp=head;

    while(temp!=NULL)

    {

        cout<<temp->alphabet<<": ";

        cout<<temp->count<<endl;

        temp = temp->next;

    }

}

void create_node() ///create 26 node for A-Z alphabet

{

    int i;

    for(i=0; i<26; i++)

    {

        node *temp=new node();

        temp ->alphabet= 97+i; ///save alphabet

        temp->count=0; ///set count =0;

        temp->next=NULL;

        if(head==NULL)

        {

            head=temp;

        }

        else

        {

            node *last=head;

            while(last->next !=  NULL)

            {

                last = last->next;

            }

            last->next=temp;

        }

    }

}

void frequency(char str[])

{

    int i=0;

    while(str[i]!=NULL)

    {

        node *temp=head;

        while(temp->next!=NULL)

        {

            if(temp->alphabet==str[i] || temp->alphabet-32==str[i]) ///compare and count frequency

            {

                temp->count++;

                break;

            }

            temp= temp->next;

        }

        i++;

    }

}

int main()

{

    create_node();

    char str[100];

    cout<<"Please Enter Any String: ";

    cin>>str;

    frequency(str);

    print_node();

    return 0;

}