Printing an Array of a Structure

Question

I have written a program in C that sorts car records by year & prints them, model & prints them, and the finds and prints the duplicates. However, the only time any records print is in the duplicate function. Otherwise, the outputs are totally blank... I have tried compiling in DevC++ and on Linux. The records are a globally declared struct and I'm printing them using a for loop... help!

Here is my code:

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

struct Car      //struct for cars
{
    char make[20];
    char model[20];
    int year;
    char color[20];
} usedCars[10] = //user inputted cars
{
    {"toyota","matrix",2006,"silver"},
    {"honda","accord",2009,"blue"},
    {"chrysler","ptcruiser",2001,"red"},
    {"volvo","xc70",2010,"blue"},
    {"chevy","blazer",2001,"black"},
    {"ford","f150",1998,"blue"},
    {"jeep","grandcherokee",2008,"red"},
    {"cadillac","deville",2004,"red"},
    {"volkswagen","jetta",2010,"silver"},
    {"chrysler","ptcruiser",2001,"red"}
};

void print_cars_by_year() //prints by year
{
    char temp[20]; //array for swapping records
    int i,j,tmp; //variables for swapping

    for (i=0; i<10; i++) // nested loop for bubble sort - repeats for 10 records
    {
        for (j=0 ; j<9; j++) //bubble sort loop
        {
            if (usedCars[j].year > usedCars[j+1].year) //if the years of the first two records are not equal
            {
                strcpy(temp, usedCars[j].make); //uses strcpy to swap the records of make
                strcpy(usedCars[j].make, usedCars[j+1].make);
                strcpy(usedCars[j+1].make, temp);

                strcpy(temp, usedCars[j].model);    //uses strcpy to swap model
                strcpy(usedCars[j].model, usedCars[j+1].model);
                strcpy(usedCars[j+1].model, temp);

                tmp = usedCars[j].year; //typical int bubble sort
                usedCars[j].year = usedCars[j+1].year;
                usedCars[j+1].year = tmp;

                strcpy(temp, usedCars[j].color);    //uses strcpy to swap color
                strcpy(usedCars[j].color, usedCars[j+1].color);
                strcpy(usedCars[j+1].color, temp);
            }
        }
    }

    printf("\nThe records sorted by year are:\n");
    printf("Make\t\tModel\t\tYear\tColor\n");
    for (i=0; i<10; i++); //prints newly sorted records
    {
        printf("%s\t%s\t%d\t%s\n",usedCars[i].make,usedCars[i].model,usedCars[i].year,usedCars[i].color);
    }
}

void print_cars_by_model()
{
    char temp[20]; //array for swapping records
    int i,j,tmp; //variables for swapping

    for (i=0; i<10; i++) // nested loop for bubble sort - repeats for 10 records
    {
        for (j=0 ; j<9; j++) //bubble sort loop
        {
            if (strcmp(usedCars[j].model, usedCars[j+1].model)>0) //if the models of the first two records are not equal
            {
                strcpy(temp, usedCars[j].make); //uses strcpy to swap the records of make
                strcpy(usedCars[j].make, usedCars[j+1].make);
                strcpy(usedCars[j+1].make, temp);

                strcpy(temp, usedCars[j].model);    //uses strcpy to swap model
                strcpy(usedCars[j].model, usedCars[j+1].model);
                strcpy(usedCars[j+1].model, temp);

                tmp = usedCars[j].year; //typical int bubble sort
                usedCars[j].year = usedCars[j+1].year;
                usedCars[j+1].year = tmp;

                strcpy(temp, usedCars[j].color);    //uses strcpy to swap color
                strcpy(usedCars[j].color, usedCars[j+1].color);
                strcpy(usedCars[j+1].color, temp);
            }
        }
    }
    printf("\nThe records sorted by model are:\n");
    printf("Make\t\tModel\t\tYear\tColor\n");
    for (i=0; i<10; i++); //prints unsorted records
    {
        printf("%s\t%s\t%d\t%s\n",usedCars[i].make,usedCars[i].model,usedCars[i].year,usedCars[i].color);
    }
}

void print_duplicate_records()
{
    int i,j;

    for (i=0; i<10; i++)
    {
        for (j=i+1; j<10; j++) //will not compare same record
        {
            if (strcmp(usedCars[i].model, usedCars[j].model) == 0) //only go if models are equal
            {
                if (strcmp(usedCars[i].make, usedCars[j].make) == 0)    //only go if makes are equal
                {
                    if (usedCars[i].year==usedCars[j].year) //only go if years are equal
                    {
                        if (strcmp(usedCars[i].color, usedCars[j].color) == 0) //if colors are equal, the record is equal
                        {
                            printf("\nThere is a duplicate record:\n");
                            printf("Make\t\tModel\t\tYear\tColor\n");
                            printf("%s\t%s\t%d\t%s\n",usedCars[i].make,usedCars[i].model,usedCars[i].year,usedCars[i].color);
                        }
                    }
                }
            }
        }
    }
}

int main()
{
    int i;
    printf("The records (unsorted) are:\n");
    printf("Make\t\tModel\t\tYear\tColor\n");
    for (i=0; i<10; i++); //prints unsorted records
    {
        printf("%s\t%s\t%d\t%s\n",usedCars[i].make,usedCars[i].model,usedCars[i].year,usedCars[i].color);
    }

    print_cars_by_year(); //call to by year func

    print_cars_by_model(); //call to by model func

    print_duplicate_records();

    return 0;
}

The output looks like

The records (unsorted) are: Make Model Year Color 0

(then the same for the two sort functions)

There is a duplicate record: Make Model Year Color chrysler ptcruiser 2001 red

Answer 1

You have a misplaced semicolon here

for (i=0; i<10; i++);
/*                  ^ what? */

this means that the code following will only execute once.

Also, please format your code, that will prevent this kind of mistake, also use compiler warnings, I didn't want to read the code because it's too messy then I tried to compile it with warnings and clang complained about the semicolon, like this

error: for loop has empty body [-Werror,-Wempty-body]

As you see, I found the problem without reading the code, because I used the tools available to check that for me.

The more important thing you should fix, is the many if statements in your code, you can use the && operator to avoid so many levels of indentation.