Question

In Language = C

Concepts for this are (malloc/realloc, structs, and stdin/fgets/getc/scanf)

Description

Your program will ask the user to type in the following information:

First Name:

Last Name:

ID#:

Email:

The program will terminate when a single . is entered as a First Name.

This information will be stored in the following structure type:

struct student {

int recordCount;

char *firstName;

char *lastName;

char *id;

char *email;

}

recordCount is a number assigned at the beginning of the program starting at 1 and increasing by 1 for each student record entered. No name (first or last) will be more than 50 characters long but you must only store the exact number of characters needed. The id will be 9 characters in length (plus end of string). You must check to see if this is the case and that each character is a decimal digit (0 to 9). If it is not, the program will tell the user this and ask for the ID# again until it is entered correctly. There is no error checking on the email input.

Any number of students can be input to the program.

After all student records have been input, the program will print out all of the records sorted by ID# (smallest to largest). The output will look like the following:

091234567,Emma,Peel,[email protected]

092345678,John,Steed,[email protected]

Sample Input and Output

$ ./enterStudents

First Name: Emma

Last Name: Peel

ID#: 091234567

Email: [email protected]

First Name: John

Last Name: Steed

ID#: 092345678

Email: [email protected]

First Name:.

091234567,Emma,Peel,[email protected]

092345678,John,Steed,[email protected]

Answer 1

main.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

// declaring structure to store student information
typedef struct student{
int recordCount;
char *firstName;
char *lastName;
char *id;
char *email;
struct student *ptr;
} student;

// function which checks if a given string is numeric or not
int containsNumber(const char *str)
{
while (*str) {
if (isdigit(*str++) == 0) return 0;
}
return 1;
}

/*
* This function is used to insert a student in the list.
* student will be added in sorted order on basis of id number(small to large)
*/

student insert(student head, int recordCount, char firstName, char lastName, char id, char email) {
student temp, prev, *next;

// create a temporary student
temp = (student*)malloc(sizeof(student));

// populate the student with information
temp->recordCount = recordCount;
temp->firstName = firstName;
temp->lastName = lastName;
temp->id = id;
temp->email = email;

temp->ptr = NULL;

// adding the student node to proper location in linked list
if(!head){
head=temp;
} else{
prev = NULL;
next = head;

// keep traversing until id is less than this node
while(next && (strcmp(next->id, id)<=0)){
prev = next;
next = next->ptr;
}

// fixing it to the correct position
if(!next){
prev->ptr = temp;
} else{
if(prev) {
temp->ptr = prev->ptr;
prev-> ptr = temp;
} else {
temp->ptr = head;
head = temp;
}
}
}
return head;
}

/*
* function used to cleanup the linked list after use
*/
void free_list(student *head) {
student *prev = head;
student *cur = head;
while(cur) {
prev = cur;
cur = prev->ptr;
free(prev->email);
free(prev->firstName);
free(prev->lastName);
free(prev->id);
free(prev);
}
}

/*
* Driver function to test
*/
int main(){

int recordCount = 0;

student head, p;
head = NULL; // head of the list where we will store student information

// temporary variable to read the line
char c[500];

// run forever, untill break
while(1) {
printf("Enter First Name:");
scanf("%s", c);

// checking if user wants to break
if(strcmp(c, ".") == 0) {
break;
}

// creating memory for firstname
char firstname = (char*)malloc((strlen(c) + 1) sizeof(char));
strcpy(firstname, c);

printf("Enter Last Name:");
scanf("%s", c);
// creating memory for lastname
char lastname = (char*)malloc((strlen(c) + 1) sizeof(char));
strcpy(lastname, c);

char *id;
while(1) {
// keep asking untill valid
printf("Enter ID:");
scanf("%s", c);
if((!containsNumber(c)) || (strlen(c) != 9)) {
printf("Error: ID should be numeric and 9 digis long only ");
continue;
}

// creating memory for id
id = (char*)malloc((strlen(c) + 1) * sizeof(char));
strcpy(id, c);
break;
}

printf("Enter Email:");
scanf("%s", c);
// creating memory for email
char email = (char*)malloc((strlen(c) + 1) sizeof(char));
strcpy(email, c);

// adding new student node to the list
head = insert(head, ++recordCount, firstname, lastname, id, email);

printf(" ");
}

// printing the records
printf(" Printing The records in sorted order:: ");
p = head;

// keep looping untill more nodes are there
while(p) {
printf("%s,", p->id);
printf("%s,", p->firstName);
printf("%s,", p->lastName);
printf("%s ", p->email);

p = p->ptr;
}

// free the allocated space after use
free_list(head);

return 0;
}

Sample Output: