Question

A Les Mills BODYPUMP instructor has a list of the weight plates for her classes and saved in a file. Each weight plate was stored with the weight (kg), color, and quantity. Write a program that reads in the data (a list of weight plates) from a file, and sort the plates by weight, and write the ordered list to the output file.

Assume the input file plates.txt has the format of weight (double), color (one word string), followed by quantity (int) with in the following format:
10 blue 16
1.25 purple 20
…

1. Name your program weight_plates.c.

2. Declare a plate structure containing information of a weight plate’s weight, color, and quantity. Assume that there are no more than 100 plates in the file. Assume that color is one word, and no more than 100 characters.

3. Use fscanf and fprintf to read and write data. The list of plates should be stored in an array of struct plate.

4. Modify the selection_sort function provided so that it sorts an array of plate struct. The plates should be sorted by weight in ascending order. The function should have the following

prototype:

void selection_sort(struct plate array_plates[], int n);

5. Output the ordered plates in a text file called ordered_plates.txt, in the same format as the input file (with two decimal digits for weight).
Suggestions:

1. Set up plate struct.
2. Use fscanf function to read the input file (note that fscanf returns number of entries filled).
3. Initially output unsorted array to screen to make sure the file input and array setup are working.
4. Modify the selection_sort function for processing plates.
5. Initially output sorted array to the screen.
6. When output is correct, write to the output file.

The txt file includes the following:

40 yellow 10

2.5 blue 18

10 grey 26

5 sliver 28

15 pink 20

45 black 12

2 gold 14

25 green 16

1. red 16

30 purple 24

1.25 black 8

20 magenta 20

35 maroon 12

Answer 1

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
/* Structure definition */
struct plate{
   double weight;
   char color[100];
   int quantity;
};

/* Function prototypes */
void selection_sort(struct plate array_plates[],int n);
void print(struct plate array_plates[],int n);
void writeToFile(struct plate array_plates[],int n);

/* Definition of main function which will open a file to read and store the datat in an array of structure.*/
int main(){
   FILE *fp;       //file pointer
   char buff[100];   //character buffer
   int i=0;
   struct plate pt[100];   //Array of plates
   fp = fopen("input.txt", "r");     //opening the file to read
   /*Iterating through the file and storing data into array */
   while(fscanf(fp, "%s", buff)!=EOF){
   pt[i].weight = atof(buff);
   fscanf(fp, "%s", buff);
   strcpy(pt[i].color,buff);
   fscanf(fp,"%s",buff);
   pt[i].quantity = atoi(buff);
   i++;
   }
   printf("Data after file reading: \n");
   print(pt,i);       //Calling print function to display data of file before sorting
   selection_sort(pt,i);   // Calling sort function to sort array according to weight in ascending order.
   printf("Data after sorting on weight: \n");
   print(pt,i);       //Calling print function to display data of file after sorting
   writeToFile(pt,i);   //Calling function to write sorted data into output file.
   fclose(fp);       //Closing file pointer
}

/*Definition of selection sort*/
void selection_sort(struct plate array_plates[],int n){
   int i,pos,j;
   struct plate temp;
   for(i=0;i<n-1;i++){
       pos = i;
       for(j=i+1;j<n;j++){
           if(array_plates[pos].weight > array_plates[j].weight)
               pos = j;
       }
       if(pos != i){
           temp = array_plates[i];
           array_plates[i] = array_plates[pos];
           array_plates[pos] = temp;
       }
   }
}

/*Definition of print function to display data on screen.*/
void print(struct plate array_plates[],int n){
   int i;
   for(i=0;i<n;i++){
       printf("%0.2f",array_plates[i].weight);
       printf(" %s",array_plates[i].color);
       printf(" %d\n",array_plates[i].quantity);
   }
}

/*Definition of writeToFile function which will write sorted datat into output.txt file.*/
void writeToFile(struct plate array_plates[],int n){
   FILE *fp;
   int i;
   fp = fopen("output.txt","w");
   for(i=0;i<n;i++){
       fprintf(fp,"%0.2f",array_plates[i].weight);
       fprintf(fp," %s",array_plates[i].color);
       fprintf(fp," %d\n",array_plates[i].quantity);
   }
   fclose(fp);
}

SCREEN SHOTS: