I have to follow this template for this assignment on Hexadecimal numerals are integers written in base 16. The 16 digits used are 0 through 9 plus a for the digit 10, b for the digit 11, c for the digit 12, d for the digit 13, e for the digit 14, and f for the digit 15.

//Input: a line of text terminated with a period, which serves as //sentinel. //Output: a list of letters sorted into decreasing order by //frequency. // //Data Structure: array of struct, struct holds a char and int //(the count). // //Algorithm: //The text is scanned a character at a time, if the character //is present in the data structure, then update the count, if //not present insert the new character in the data structure, //update the count to 1. The array of structs is sorted on //the count key.

#include #include #include

struct char_freq { char ch; int count; };

//NOTE that all that is necessary in the headers is to //replace int with char_freq

void sort(char_freq a[], int number_used); //Precondition: number_used <= declared size of the array a. //The array elements a[0] through a[number_used - 1] have //values. //Postcondition: The values of a[0] through //a[number_used - 1] have been rearranged so that //a[0] <= a[1] <= ... <= a[number_used - 1].

void swap_values(char_freq& v1, char_freq& v2); //Interchanges the values of v1 and v2.

int index_of_largest(const char_freq a[], int start_index, int number_used); //Precondition: 0 <= start_index < number_used. //Referenced array elements have values. //Returns the index i such that a[i].count is the largest of //the values //a[start_index].count, a[start_index + 1].count, ..., //a[number_used - 1].count

void input( char_freq list[], int& size); //list is an array of char_freq structs. //reads input, period is sentinel. Sets the char members of the //char_freq struct elements of list to newly occurring characters, // otherwise, if the struct already has the character, this routine // increments the count for that character.

void output( char_freq list[], int size ); //lists Letter, Number of Occurrences in columns

bool lookup( char c, char_freq list[], int& size ); //traverses the elements of list through size elements //if an element containing c is found, // increment count in the list member for that character // returns true (1) (c is in the list) //else // returns false(0) (c is not in the list)

void insert( char c, char_freq list[], int& size ); //precondition: c is not in the list //post condition: c has been added in position size, //size has been incremented. //size <= 26

int main() { char_freq list[50] ={0,0}; //we are going to pick up //punctuation, etc. int list_size = 0; input( list, list_size ); sort( list, list_size ); output( list, list_size); return 0; }

void input(char_freq list[], int& size) { using namespace std; char ch; cin >> ch; //we want to ignore blanks, so we use cin >>... ch = tolower(ch); // Push everything to lowercase. while('.' != ch) { if (!lookup(ch, list, size)) insert(ch, list, size); cin >> ch; } }

void insert(char c, char_freq list[], int& size) { list[size].count=1; list[size].ch = c; size ++; assert( size <= 26); }

bool lookup(char c, char_freq list[], int& size) { int i = 0; bool success = false; // Complete the function return success; } void output( char_freq list[], int size ) { using namespace std; cout << "Letter:\tNumber of Occurrences." << endl; for ( int i = 0; i < size; i++) cout << list[i].ch << '\t' << list[i].count << endl; }

void sort(char_freq a[], int numberUsed) { // Complete the function } void swap_values(char_freq& v1, char_freq& v2) { // Complete the function } int index_of_largest(const char_freq a[], int startIndex, int numberUsed) { // Complete the function

return indexOfMax; }