Python
```python
n = int(input("请输入菱形的边长: "))
s = '* '
for i in range(1, n + 1):
print((s * i).center(2 * n, " "))
for i in range(n - 1, 0, -1):
print((s * i).center(2 * n, " "))
```
Java
```java
import java.util.Scanner;
public class Diamond {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("请输入菱形的边长: ");
int n = scanner.nextInt();
String s = "* ";
for (int i = 1; i <= n; i++) {
System.out.println((s + " ".repeat(n - i)).center(2 * n, " "));
}
for (int i = n - 1; i > 0; i--) {
System.out.println((s + " ".repeat(n - i)).center(2 * n, " "));
}
}
}
```
C++
```cpp
include include include int main() { int n; std::cout << "请输入菱形的边长: "; std::cin >> n; std::string s = "* "; for (int i = 1; i <= n; i++) { std::cout << std::string(n - i, ' ') << std::string(2 * i - 1, '*') << std::endl; } for (int i = n - 1; i > 0; i--) { std::cout << std::string(n - i, ' ') << std::string(2 * i - 1, '*') << std::endl; } return 0; } ``` C ```c include int main() { int n; printf("请输入菱形的边长: "); scanf("%d", &n); int space = n - 1; for (int k = 1; k <= n; k++) { for (int c = 1; c <= space; c++) { printf(" "); } space--; for (int c = 1; c <= 2 * k - 1; c++) { printf("*"); } printf("\n"); } space = 1; for (int k = 1; k <= n - 1; k++) { for (int c = 1; c <= space; c++) { printf(" "); } space++; for (int c = 1; c <= 2 * (n - k) - 1; c++) { printf("*"); } printf("\n"); } return 0; } ``` 这些代码示例分别展示了如何在Python、Java、C++和C语言中输入边长n并输出菱形星号。你可以选择适合你的编程语言进行尝试。