C语言计算n的阶乘；计算1*3*5*7*....*(2n+1)

Sure, I can help you with that. Here's a code snippet in C language to calculate the factorial of n:

#include <stdio.h>

int main() {
  int n, i, factorial = 1;

  printf("Enter a number: ");
  scanf("%d", &n);

  for (i = 1; i <= n; i++) {
    factorial *= (2*i - 1);
  }

  printf("Factorial of %d is %d\n", n, factorial);

  return 0;
}

This program uses a `for` loop to iterate through the odd numbers (`2n-1`) up to `2n-1`, and multiplies them together to calculate the factorial of n.