C程序：从文件读取和复制到结构？

Question

I'm working on an assignment for a class and I'm having trouble applying file input/output and structs together. I have this code that reads different cars from a file and copies their information into an array of structs.

#include <stdio.h>

#define MAX_LEN 1000 
#define NAME_LEN 30

struct car{
    char make[NAME_LEN + 1];
    char model[NAME_LEN + 1];
    int year;
    int cmpg;
    int hmpg;
    int avgmpg;
};
.
.
.
int main()
{
    int i;

    struct car cars[MAX_LEN];

    FILE* pFile;
    pFile = fopen("cars.txt", "r");

    .
    .
    .
    .

    for(i = 0; i < MAX_LEN; i++)
    {
        while(!feof(pFile) && !ferror(pFile))
            {
            fscanf(pFile, "%s%s%d%d%d ", cars[i].make, cars[i].model, &cars[i].year, &cars[i].cmpg, &cars[i].hmpg);
            cars[i].avgmpg = (cars[i].cmpg + cars[i].hmpg) / 2;
        }
    }

    selection_sort(cars, MAX_LEN);

    FILE* outFile;
    outFile = fopen("sorted_cars.txt", "w");

    fprintf(outFile, "Make     Model year  city mpg  highway mpg average mpg\n");

    for(i = 0; i < MAX_LEN; i++);
    {   
        fprintf(outFile, "%s %s %d %-2d %-10d %-12d\n", cars[i].make, cars[i].model, cars[i].year, cars[i].cmpg, cars[i].hmpg, cars[i].avgmpg); 
        printf("%s %s %d %d %d %d\n", cars[i].make, cars[i].model, cars[i].year, cars[i].cmpg, cars[i].hmpg, cars[i].avgmpg);
    }


    fclose(pFile);
    fclose(outFile);
    return 0;
    }

This is what the .txt file looks like:

Mercury Sable 2009 18 28
Jeep Wrangler 2016 17 21
Honda Civic 2015 31 41
Toyota Corolla 2015 30 42
Toyota Prius 2010 51 48
Ford Escape 2013 23 33
Ford Fusion 2013 25 37
Acura MDX 2014 20 28
Lexus RX 2013 32 28

I inserted a print function into my code so I could see if the cars read properly, but when I run the program, this is the output:

▒▒▒8 0 0 1465899048 32767

I have absolutely no idea why this is happening. Can anybody help?

Answer 1

First remove while() and put if(!feof(pFile) && !ferror(pFile)) . In your fscanf() for cars file put spaces between type specifiers. It should be like this

fscanf(pFile, "%s %s %d %d %d", cars[i].make, cars[i].model, &cars[i].year, &cars[i].cmpg, &cars[i].hmpg); cars[i].avgmpg = (cars[i].cmpg + cars[i].hmpg) / 2;

And before directly writing to the file, first print the values of struct in console only, and whether you are getting it in proper way or not.

And the last modification is Instead of using this

fprintf(outFile, "%s %s %d %-2d %-10d %-12d\n", cars[i].make, cars[i].model, cars[i].year, cars[i].cmpg, cars[i].hmpg, cars[i].avgmpg);

Use this

fprintf(outFile, "%s %s %d %d %d %d\n", cars[i].make, cars[i].model, cars[i].year, cars[i].cmpg, cars[i].hmpg, cars[i].avgmpg);

I hope this will help you.