Sorter fil indhold i C

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

struct info
{
  char *name;
  int grade;
};

void qs_help(int n1,int n2,struct info *a)
{
  struct info tmp;
  int l = n1;
  int r = n2;
  int pivot = a[(n1+n2)/2].grade;
  do {
      while(a[l].grade<pivot) l++;
      while(a[r].grade>pivot) r--;
      if(l<=r) {
        tmp = a[l];
        a[l] = a[r];
        a[r] = tmp;
        l++;
        r--;
      }
  } while(l<=r);
  if(n1<r) qs_help(n1,r,a);
  if(l<n2) qs_help(l,n2,a);
  return;
}

void qs(int n,struct info *a)
{
  qs_help(0,n-1,a);
  return;
}

#define KEY1 "Name:"
#define KEY2 "Grade:"

int main()
{
  int i,n;
  char line[133],*p1,*p2;
  struct info data[5000];
  FILE *fp = fopen("z.z", "r");
  n=0;
  while(!feof(fp)) {
      if(fgets(line,sizeof(line),fp))
      {
          p1 = strstr(line,KEY1) + strlen(KEY1);
          while(*p1==' ') p1++;
          p2 = strchr(p1,' ');
          data[n].name = (char *)malloc(p2-p1);
          strncpy(data[n].name,p1,p2-p1);
          data[n].name[p2-p1] = '\0';
          data[n].grade = atoi(strstr(line,KEY2)+strlen(KEY2));
          n++;
      }
  }
  fclose(fp);
  printf("usorteret:\n");
  for(i=0;i<n;i++)
  {
      printf("%d,\"%s\"\n",data[i].grade,data[i].name);
  }
  qs(n,data);
  printf("sorteret:\n");
  for(i=0;i<n;i++)
  {
      printf("%d,\"%s\"\n",data[i].grade,data[i].name);
  }
  return 0;
}

Output på dine test data:

usorteret:
10,"John"
2,"Hans"
5,"Mads"
3,"Allan"
sorteret:
2,"Hans"
3,"Allan"
5,"Mads"
10,"John"

Kan klare op til 5000 records. Og det tal kan nemt øges. Det er nok lidt
bøvlet at gøre det helt dynamisk i C.

Koden validerer ikke data men forventer korrelt input.

Udskrivning til fil er bare:

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

struct info
{
  char *name;
  int grade;
};

void qs_help(int n1,int n2,struct info *a)
{
  struct info tmp;
  int l = n1;
  int r = n2;
  int pivot = a[(n1+n2)/2].grade;
  do {
      while(a[l].grade<pivot) l++;
      while(a[r].grade>pivot) r--;
      if(l<=r) {
        tmp = a[l];
        a[l] = a[r];
        a[r] = tmp;
        l++;
        r--;
      }
  } while(l<=r);
  if(n1<r) qs_help(n1,r,a);
  if(l<n2) qs_help(l,n2,a);
  return;
}

void qs(int n,struct info *a)
{
  qs_help(0,n-1,a);
  return;
}

#define KEY1 "Name:"
#define KEY2 "Grade:"

int main()
{
  int i,n;
  char line[133],*p1,*p2;
  struct info data[5000];
  FILE *fp,*fp2;
  fp = fopen("z.z", "r");
  n=0;
  while(!feof(fp)) {
      if(fgets(line,sizeof(line),fp))
      {
          p1 = strstr(line,KEY1) + strlen(KEY1);
          while(*p1==' ') p1++;
          p2 = strchr(p1,' ');
          data[n].name = (char *)malloc(p2-p1);
          strncpy(data[n].name,p1,p2-p1);
          data[n].name[p2-p1] = '\0';
          data[n].grade = atoi(strstr(line,KEY2)+strlen(KEY2));
          n++;
      }
  }
  fclose(fp);
  qs(n,data);
  fp2 = fopen("zz.zz", "w");
  for(i=0;i<n;i++)
  {
      fprintf(fp2,"%s %s %s %d\n",KEY1,data[i].name,KEY2,data[i].grade);
  }
  fclose(fp2);
  return 0;
}

Woooohooooooo :)

Det virker helt perfekt!!

Mange tusinde tak.