Thread: Problem with output after sorting *Help*

recently i have wrote a program. But unfortunately the program doesn't run well and i have no idea what should i do.....can any one so kind to help me? Thank!

Code:

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define N 7


typedef struct Date
{
    unsigned  day;
    unsigned  month;
    unsigned  year;
}DATE;


typedef struct Video
{
unsigned id;
char title[90];
char producer[60];
DATE releaseDate;
} VIDEO;


VIDEO v[N]={};
unsigned noOfVideo=0;


void purgeKBBuffer() /* delete characters left in the keyboard buffer */
{
 int dummychar;
 /* read and drop characters from the buffer
 until the closing return ('\n') is reached */
 do dummychar = getchar();
 while (dummychar != '\n');
 }


char* inputString(char x[], int SIZE)
{
 int i=-1;
do
 {
 x[++i] =getchar();
 }
 while(x[i]!='\n'&&i<SIZE);


x[i]='\0';
return x;
}


DATE inputDate()
{
 DATE d;
 printf("Enter Day:");
 scanf("%u", &d.day);
 purgeKBBuffer();
 printf("Enter Month:");
 scanf("%u", &d.month);
 printf("Enter Year:");
 scanf("%u", &d.year);
 putchar('\n');


return d;
}


VIDEO inputVideo()
{
VIDEO v;
printf("ID:");
scanf("%u",&v.id);
purgeKBBuffer();
printf("Title:");
inputString(v.title,90);
printf("Producer:");
inputString(v.producer,60);
printf("The released date:\n");
v.releaseDate=inputDate();
return v;
}


void addVideo(VIDEO v[N])
{
 if(noOfVideo<N)
 {
 v[noOfVideo]=inputVideo();
 noOfVideo++;
 }


else
 {
 printf("The database can only store up to 7 videos and there is no space left!\n\n");
 }
}


void printVideo(VIDEO v)
{
    printf("\nID:%u\tTitle:%s\t\tProducer:%s\tRelease Date:%u.%u.%u", v.id, v.title, v.producer, v.releaseDate.day, v.releaseDate.month, v.releaseDate.year);
    printf("\n");
}


void listVideos(VIDEO v[noOfVideo])
{
int i;
 for(i=0;i<noOfVideo;i++)
 {
 printVideo(v[i]);
 }
 }


void sortById(VIDEO v[N])
{
VIDEO temp;
int lower,Min,i;
for (lower=0;lower<=N-2;lower++)
   {
     Min=lower;
     for (i=lower+1;i<N;i++)
        {
          if (v[i].id<v[Min].id)
            {
              Min=i;
            }
        }
     temp=v[lower];
     v[lower]=v[Min];
     v[Min]=temp;
   }
}


void findAndPrintVideoByTitle(VIDEO v[N])
{
int i, j = 0;
char title[90];
printf("\tPlease enter title to search: ");
inputString(title,90);
putchar('\n');
for(i = 0; i <= N-1; i++)
{
if (strcmp (v[i].title, title) == 0)
{
j = 1;
printVideo(v[i]);
}
}
if (j == 0)
{
printf("\tVideo not found!\n\n");
}
}


char actionMenu()
/* show the menu and return a valid selection of the menu */
{
char z;
printf("\t\t\t**************************\n\n");
printf("\t\t\t*     Video Database     *\n\n");
printf("\t\t\t**************************\n\n");
printf ("\t(a) Add a video.\n");
printf ("\t(b) List all videos\n");
printf ("\t(c) Sort videos by ID\n");
printf ("\t(d) Search a video by title\n");
printf ("\t(e) Quit\n\n\t");
// get user input
do z = (char) getchar();
// continue while c not found in the string of menu chars
while (strchr("abcde", z) == 0);
printf("\n");
purgeKBBuffer();
return z;
}




int main()
{
 VIDEO v[N];
 char actionMenu();
 char z;
 unsigned Count = 0;
while (z != 'e')
{
z = actionMenu();


switch (z)
{
case 'a': addVideo(v); // TODO add a new video
break;
case 'b': listVideos(v); // TODO list all videos
break;
case 'c': sortById(v); // TODO sort video by id
break;
case 'd': findAndPrintVideoByTitle(v); // TODO find video by title
break;
case 'e': printf("\tBye!\n\n"); //end program
break;
default: printf("invalid input\n");break;
}
}




return 0;
}

in order to sort you need to enter "c" and to print out you need to type in "b" again. But that's the problem....

somehow it didnt show the data after sorting. it show 0 0 0

Originally Posted by whiteflags

Code:

bool idcomp(const VIDEO* array, int currMin, int k)
{
  return array[k].id < array[currMin].id;
}

.

Thank by the way, What is the usage of this?

Well separating the comparison from the algorithm like that helps you extend the usefulness of the algorithm.

You pass it in like this in main:

Code:

selectionSort(array, n, compid);

Inside the algorithm, compid will be called, under a different name. You can also create functions that compare differently, and use those the same way.

More information can be found at The Function Pointer Tutorials.