C++ :

#include <iostream>
#include <iomanip>

using namespace std;

int main(){
	int n,m,t,i,a[1000];
	cin>>n>>m>>t;
	for(i=0;i<n;i++){
		cin>>a[i];
	}
	for(i=0;i<n;i++){
		cout<<a[i]<<" ";
		if(m==a[i]){
			cout<<t<<" ";
		}
	}
}

Pascal :

var i,t:integer; 
    a:array[1..100] of longint; 
    n,x,y:longint;
begin
  readln(n,x,y);
  for i:=1 to n do
    read(a[i]);
  for i:=1 to n do
    if a[i]=x then
    begin
      t:=i+1;
      break;
    end;
   for i:=n downto t do
     a[i+1]:=a[i];
   a[t]:=y; 
   for i:=1 to n do write(a[i],' ');
   write(a[n+1]);
   readln;
   readln;
end.

Java :

import java.util.Scanner;

public class Main {
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		int n=sc.nextInt();
		int x=sc.nextInt();
		int y=sc.nextInt();
		int[] a=new int[n];
		for(int i=0;i<n;i++){
			a[i]=sc.nextInt();
		}
		int po=0;
		for(int i=0;i<n;i++){
			if(a[i]==x){
				po=i;
			}
		}
		int[] b=new int[n+1];
		for(int i=0;i<=po;i++){
			b[i]=a[i];
		}
		b[po+1]=y;
		for(int i=po+2;i<n+1;i++){
			b[i]=a[i-1];
		}
		for(int i=0;i<n+1;i++){
			System.out.print(b[i]+" ");
		}
	}
	
}

Python :

n,f,b=list(map(int,input().split()))
m=list(map(int,input().split()))
i=m.index(f)
m.insert(i+1,b)
for item in m:
    print(item,end=" ")