Correct code is

Code:
#include<stdio.h>
#include<stdlib.h>

#define MAX 10
int a[MAX];
void input(int);
int search_no(int );
main()
{
	int n,i,search,pos;
	int ch;
	while(1)
	{
		printf("\n Enter The Choice");
		printf("\n1.Input");
		printf("\n2.Display");
		printf("\n3.Search");
		printf("\n .Exit");
		scanf("%d",&ch);

		switch(ch)
		{
		case 1: printf("\nEnter the number");
				scanf("%d",&n);
				input(n);//no return 
				break;
				
		case 2: printf("Display number\n");
				for(i=0;i<=n-1;i++)
				{
					printf("%d\n",a[i]);
				}
				break;
		case 3:printf("Enter the number to search\n");
				scanf("%d",&search);
				pos=search_no(search);  //remove int 
        break;
		default:
        exit(0);
		}
	}
}
void input(int n)
{
		int i;
		printf("\n Enter the element");
		for(i=0;i<=n-1;i++)
			scanf("%d",&a[i]);
}				
int search_no(int search)
{
	int i,n;
	for(i=0;i<=n-1;i++)
	{
		if(search==a[i])
			return(i+1);
	}return(0);
}