024.寻找指定元素的指针

#include <stdio.h>
#define MAX 20
int search(int *apt,/*已知数表的首元指针*/
  int n,/*数表中元素个数*/
  int key)/*要寻找的值*/
{
  int *p;
  for(p=apt;p<apt+n;p++)
    if(*p==key)
      return p-apt;/*返回找到元素的下标*/
  return -1;
}
int *find(int *apt,/*已知数表的首元指针*/
    int n,/*数表中元素个数*/
    int key)/*要寻找的值*/
{
  int *p;
  for(p=apt;p<apt+n;p++)
    if(*p==key)
    return p;/*返回找到元素的指针*/
  return NULL;
}
int a[]={90,80,70,60,50,40,30,20,10,9,8,7,6,5,42,40,50,1,2,3};
main()
{
  int i,key;
  clrscr();
  printf("The elements of array a is:\n");
  for(i=0;i<sizeof(a)/sizeof(a[0]);i++)
    printf(" %d",a[i]);
  printf("\nThe address of a[0] is: %d.\n",&a[0]);
  puts("\nPlease input the key number you want to search:");
  scanf("%d",&key);
  i=search(a,sizeof(a)/sizeof(a[0]),key);
  printf("\nThe label number of the key number %d in the array is: %d.",key,i);
  printf("\nThe point value of the key number %d in the array is: %d.",key,find(a, sizeof(a)/sizeof(a[0]),key));
  puts("\n\n Press any key to quit...");
  getch();
}