```cpp
#include<bits/stdc++.h>
using namespace std;
bool sushu(int x){
bool r=true;
for(int i=2;i*i<=x;i++){
if(x%i==0){
r=false;
break;
}
}
if(x<=1){
r=false;
}
return r;
}
int main() {
int i,j,x;
int n;
cin>>n;
for(i=4;i<=n;i+=2) {
for(j=2;j<=i;j++) {
x=i-j;
if(sushu(j)&&sushu(x)) {
if(x>j){
swap(j,x);
}
cout<<i<<'='<<x<<'+'<<j<<endl;
}
}
}
return 0;
}
```
by zjx331 @ 2023-04-29 10:55:27
如果这题做不出来，就是基础知识没有掌握好
by zjx331 @ 2023-04-29 10:56:06
@[LF17783001688](/user/721324) 你可以看题解啊
by SlaineTroyard @ 2023-04-29 11:01:06
谢谢，但我自己之前做过，但WA了能帮看看吗？
```cpp
#include <bits/stdc++.h>
using namespace std;
bool prime(int n)
{
if(n<=1) return false;
for(int i=2;i<=sqrt(n);i++) if(n%i==0) return false;
return true;
}
void gold(int n)
{
for(int i=2;i<=n;i++)
{
if(prime(i)&&prime(n-1))
{
printf("%d=%d+%d\n",n,i,n-i);
return;
}
}
}
int main()
{
int n;
cin>>n;
for(int i=4;i<=n;i+=2) gold(i);
return 0;
}
by LF17783001688 @ 2023-04-29 11:01:28
@[LF17783001688](/user/721324)
>prime(n-1)
是n-i吧
by cff_0102 @ 2023-04-29 11:02:51
额，自己没有注意 谢谢个位大佬
by LF17783001688 @ 2023-04-29 11:05:02
```cpp
#include <cstdio>
#include <algorithm>
using namespace std;
bool is_prime(int x)
{
for(int i = 2;i * i <= x;i++)
{
if(x % i == 0)
return false;
}
return true;
}
void write(int a)
{
if(a == 4)
{
printf("4=2+2\n");
return;
}
for(int i = 3;i + 2 <= a;i += 2)
{
if(is_prime(i) && 2 + i == a)
{
printf("%d=2+%d\n",a,i);
return;
}
}
for(int i = 3;i + 3 <= a;i += 2)
{
if(is_prime(i) && is_prime(a - i))
{
printf("%d=%d+%d\n",a,min(i,a - i),max(i,a - i));
return;
}
}
}
int n;
int main()
{
scanf("%d",&n);
for(int i = 4;i <= n;i += 2)
write(i);
return 0;
}
```
by ChenyangGu @ 2023-06-18 15:13:56
AC了没？
by ChenyangGu @ 2023-06-18 15:14:34