42 date：2021.3.21

要點：
calloc 用於分配記憶體空間，形式： (型別說明符)calloc(n,size)
在記憶體動態儲存區中分配n塊長度為"size"位元組的連續區域，函式的返回值為該區域的首地址
(型別說明符*)用於強制型別轉換。

calloc函式與malloc函式的區別在於calloc函式一次可以分配n塊區域

詳細程式碼如下：

#include <stdlib.h>
#include  <conio.h>
#include  <string.h>
#include  <stdio.h>
#include
 
  <malloc.h>
#define N 10
typedef struct ss
   { char num[10];
     int s;
   } STU;
STU *fun(STU a[], int m)
{ STU b[N],*t;
  int i, j,k;
/*************found**************/
  t=(STU*)calloc(m,sizeof(STU));
  for(i=0;i<N;i++) b[i]=a[i];
  for(k=0;k<m;k++)
     { for (i=j=0;i<N;i++)
          if
 
(b[i].s>b[j].s) j=i;
/*************found**************/
     strcpy(t[k].num,b[j].num);  //因為num是陣列型別，所以不可以直接用t[k].num = b[j].num這種賦值辦法
      t[k].s=b[j].s;
      b[j].s=0;
     }
return t;
}
void outresult(STU a[],FILE *pf)
{ int i;
  for(i=0;i<N;i++)
  fprintf(pf, "No=%s Mark=%d\n ",
a[i]
 
.num, a[i].s);
  fprintf(pf, "\n\n ");
}
void main()
{ STU a[N]={{ "A01 ",81},{ "A02 ",89},{ "A03 ",66},{ "A04 ",87},{ "A05 ",77},
			{ "A06 ",90},{ "A07 ",79},{ "A08 ",61},{ "A09 ",80},{ "A10 ",71}};
  STU *pOrder;
  int i, m;
  system("CLS");
  printf("*****THE RESULT*****\n");
  outresult(a,stdout);
  printf("\nGive the number of the students who have better score: ");
  scanf("%d",&m);
  while(m>10)
       { printf("\nGive the number of the students who have better score: ");
  scanf("%d",&m);
}
  pOrder=fun(a,m);
  printf("***** THE RESULT*****\n");
  printf("The top :\n");
  for(i=0;i<m;i++)
     printf("%s  %d\n",pOrder[i].num, pOrder[i].s);
  free(pOrder);
}

要點：
注意下標

詳細程式碼如下：

#include <stdio.h>
#define N 80
int fun(int a[], int n)
{
  /*
	analyse:


  */
	int i , j = 1;
	for(i = 1; i<n; i++)
	{
		if(a[i] != a[i-1]) //若該數與前一個數不相同，則要保留
			a[j++] = a[i];
		
	}
	return j; //返回不相同的個數

 /*
 int i,j=0;

 for(i =  0; i<20; i++)
 {
	if(a[i] == a[i+1])
		a[j] =a[i];
 }
 */
}
void main()
{ 
  FILE *wf;
  int a[N]={ 2,2,2,3,4,4,5,6,6,6,6,7,7,8,9,9,10,10,10,10}, i, n=20;
  printf("The original data :\n");
  for(i=0; i<n; i++)  
     printf("%3d",a[i]);
  n=fun(a,n);
  printf("\n\nThe data after deleted :\n");
  for(i=0; i<n; i++)  
     printf("%3d",a[i]);  
  printf("\n\n");
/******************************/
  wf=fopen("out.dat","w");
  for(i=0; i<n; i++)  
     fprintf(wf,"%3d",a[i]);
  fclose(wf);
/*****************************/
}