C#求大神解答，拜托拜托

public static void Main(string[l args) for(int i = 3;ic=18;it+)[ bool flag = true,
 for(int k - 2.k<-i-1;kt+){
 if(i%k == 0)
 flag = false;

 if(flag =- false)[
 Console.write(“ (0):”,i)

 public static void Main(stringl args)
 int[]a = (1, 3,4, 12, 5, 2, 7); int i =4:
 int pivot = a[i]; int s =i-1; for(; s>=0;s--) {

]else {
 break

 a[s+1] = pivot;
 foreach(int k in a)l
 Console.Write(k)

.public static void Main(stringl] args)

 int count = 0;     for(int 3 i(19;it=2)(
 bool flag =true,
 bfor(int k - 2.kk-i-1;k++)(
 if(i%k =- 0)
 flag + false; break

 if(flag)(
 cansole.Hrite(" (0]*“,i):     count++;
 if(count %4 - 0) Console.writeLine()