Question

create case 4 do Method 1:copy item by item and skip the item you want to delete after you are done, delete the old file and rename the new one to the old name.

#include 
int main(void) {
        int counter;
        int choice;
        FILE *fp;
        char item[100];
        while(1) {
                printf("Welcome to my shopping list\n\n");
                printf("Main Menu:\n");
                printf("1. Add to list\n");
                printf("2. Print List\n");
                printf("3. Delete List\n");
                printf("4. Remove an item from the List\n");
                printf("5. Exit\n\n");


                scanf("%i", &choice);
                switch(choice) {
                        case 1: //add to list
                                //get the input from the user
                                printf("Enter item: ");
                                scanf("%s", item);
                                //open the file
                                fp = fopen("list.txt","a");
                                //write to the file
                                fprintf(fp, "\n%s", item);
                                //close the file
                                fclose(fp);
                        break;
                        case 2: //print list
                                //open the file
                                fp = fopen("list.txt","r");
                                //while we are not at the end of the file
                                counter = 1;

                                //cheat to make feof work! 
                                char c = fgetc(fp);
                                ungetc(c, fp);
                                while (!feof(fp)) {
                                        //read in a line of data
                                        fscanf(fp, "%s", item);
                                        //print the data
                                        printf("%i. %s\n", counter,item);
                                        counter++;
                                }
                                //close the file
                                fclose(fp);
                        break;
                        case 3: //erase list
                                //truncate the file
                                fp = fopen("list.txt","w");
                                fclose(fp);


                        break;
                        case 4: //homework: remove an item from the list;

                        /*
                                Method 1:
                                        0) Get the item number the user wants to delete
                                        char data[100][100];
                                        1) Create an array of strings
                                        2) Loop over the items in the list, loading into the array
                                                -skip if it's the item the user wants to delete
                                        3) Loop over the array, writing out to the file. 


                        */

                        break;
                        case 5: //end program
                                return 0; 
                        break;




                }

        }

Answer 1

If you have any doubts, please give me comment...

#include <stdio.h>

#include <string.h>

int main(void)

{

    int counter;

    int choice;

    FILE *fp;

    char item[100];

    while (1)

    {

        printf("Welcome to my shopping list\n\n");

        printf("Main Menu:\n");

        printf("1. Add to list\n");

        printf("2. Print List\n");

        printf("3. Delete List\n");

        printf("4. Remove an item from the List\n");

        printf("5. Exit\n\n");

        scanf("%i", &choice);

        switch (choice)

        {

        case 1: //add to list

            //get the input from the user

            printf("Enter item: ");

            scanf("%s", item);

            //open the file

            fp = fopen("list.txt", "a");

            //write to the file

            fprintf(fp, "\n%s", item);

            //close the file

            fclose(fp);

            break;

        case 2: //print list

            //open the file

            fp = fopen("list.txt", "r");

            //while we are not at the end of the file

            counter = 1;

            //cheat to make feof work!

            char c = fgetc(fp);

            ungetc(c, fp);

            while (!feof(fp))

            {

                //read in a line of data

                fscanf(fp, "%s", item);

                //print the data

                printf("%i. %s\n", counter, item);

                counter++;

            }

            //close the file

            fclose(fp);

            break;

        case 3: //erase list

            //truncate the file

            fp = fopen("list.txt", "w");

            fclose(fp);

            break;

        case 4: //homework: remove an item from the list;

            /*

            Method 1:

                0) Get the item number the user wants to delete

                char data[100][100];

                1) Create an array of strings

                2) Loop over the items in the list, loading into the array

                        -skip if it's the item the user wants to delete

                3) Loop over the array, writing out to the file.

            */

            {

                char data[100][100];

                printf("Enter item to delete: ");

                scanf("%s", item);

                fp = fopen("list.txt", "r");

                counter = 1;

                //cheat to make feof work!

                char c = fgetc(fp);

                ungetc(c, fp);

                while (!feof(fp))

                {

                    //read in a line of data

                    fscanf(fp, "%s", data[counter]);

                    if (strcmp(data[counter], item) != 0)

                        counter++;

                }

                //close the file

                fclose(fp);

                fp = fopen("list.txt", "w");

                int i;

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

                {

                    //write to the file

                    fprintf(fp, "\n%s", data[i]);

                }

                //close the file

                fclose(fp);

            }

            break;

        case 5: //end program

            return 0;

            break;

        }

    }

}