Question

Write a program that stores lists of names (the last name first) and ages in parallel arrays and sorts the names into alphabetical order keeping the ages with the correct names. The original arrays of names and ages should remain no changes. Therefore, you need to create an array of character pointers to store the addresses of the names in the name array initially. Apply the selection sort to this array of pointers so that the corresponding names are in alphabetical order.

Answer 1

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

#define STRSIZ 30

#define MAXAPP 50

int alpha_first(char *list[], int min_sub, int max_sub);

void select_sort_str(char *list[], int * numbers[], int n);

int main()

{

char applicants[MAXAPP][STRSIZ];

int ages[MAXAPP];

char* alpha[MAXAPP];

int* numeric[MAXAPP];

int num_app, i, j;

char one_char;

printf("Enter number of people (0 . . %d)\\> ", MAXAPP);

scanf("%d", &num_app);

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

{

scanf("%c", &one_char);

printf("\\Enter name %d (lastname, firstname): ", i + 1);

j = 0;

while ((one_char = (char)getchar()) != '\\' && j < STRSIZ)

applicants[i][j++] = one_char;

applicants[i][j] = '\0';

printf("Enter age %d: ", (i + 1));

scanf("%d", &ages[i]);

alpha[i] = (char*)malloc(strlen(applicants[i]) * sizeof(char));

strcpy(alpha[i], applicants[i]);

numeric[i] = &ages[i];

}

printf("\\\\Original list");

printf("\\---------------------------\\");

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

printf("%-30s%2d\\", applicants[i], ages[i]);

select_sort_str(alpha, numeric, num_app);

printf("\\\\Alphabetized list");

printf("\\---------------------------\\");

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

printf("%-30s%2d\\", alpha[i], *numeric[i]);

printf("\\\\Original list");

printf("\\---------------------------\\");

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

printf("%-30s%2d\\", applicants[i], ages[i]);

return 0;

}

int alpha_first(char* list[], int min_sub, int max_sub)

{

int first, i;

first = min_sub;

for (i = min_sub + 1; i <= max_sub; ++i)

if (strcmp(list[i], list[first]) < 0)

first = i;

return (first);

}

void select_sort_str(char* list[], int* numbers[], int n)

{

int fill, index_of_min;

char* temp;

int* tempNum;

for (fill = 0; fill < n - 1; ++fill)

{

index_of_min = alpha_first(list, fill, n - 1);

if (index_of_min != fill)

{

temp = (char*)malloc(strlen(list[fill]) * sizeof(char));

strcpy(temp, list[index_of_min]);

strcpy(list[index_of_min], list[fill]);

strcpy(list[fill], temp);

tempNum = numbers[index_of_min];

numbers[index_of_min] = numbers[fill];

numbers[fill] = tempNum;

}

}

}