Suppose there is an array a with 5 elements, and 5 elements of the array are input through the keyboard. Call the sub-function to store the array elements in reverse

Array storage in reverse order can be implemented without pointers. As mentioned in
the previous blog, this sharing focuses on pointer implementation.

Code display:

#include <stdio.h>
void fan(int *x,int n);
int  main()
{
    
    
 int i,arr[5],*p=arr; //定义一个数组，再定义指针变量将数组名赋值给指针变量。
 printf("The original array:\n");
 for(i=0;i<5;i++,p++)
   scanf("%d",p);//作输入p即表示每一个数组元素的地址
 printf("Output:\n");

p=arr;//再次赋值传递给子函

 fan(p,5); 
 printf("The array has been inverted:\n");
 for(p=arr;p<arr+5;p++)
   printf("%d ",*p);
 printf("\n");
 return 0;
}

void fan(int *x,int n)
 {
    
    

int temp,i;

for(i=0;i<n/2;i++)
{
    
    
	temp=*(x+i);
	*(x+i)=*(x+n-i-1);
	*(x+n-i-1)=temp;
}

 }

Code analysis is reflected in the code one by one.

for(i=0;i<n/2;i++)
{
    
    
	temp=*(x+i);
	*(x+i)=*(x+n-i-1);
	*(x+n-i-1)=temp;
}

This part is the core algorithm, stored in reverse order. It is not easy to come up with this algorithm at the beginning. For me, most of the C language topics are like finding the rules. The algorithm is really hard to think about. If you are interested, you can buy an introduction to the algorithm.