よくある問題/階乗 - C/C++の宿題を片付けます@wiki

階乗

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ループで階乗を求める

C

#include<stdio.h>
unsigned int factorial( unsigned int n)
{
  unsigned int result = 1;
  while(n != 0) result *= n, --n;
  return result
}
int main( void )
{
  int n;
  printf("nを入力：");
  scanf("%d", &n);
  printf("%dの階乗は%d\n", n, factorial(n));
  return 0;
}

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再帰で階乗を求める

C

#include<stdio.h>
unsigned int factorial( unsigned int n)
{
  return n == 0 ? 1 : n * factorial(n-1);
}
int main( void )
{
  int n;
  printf("nを入力：");
  scanf("%d", &n);
  printf("%dの階乗は%d\n", n, factorial(n));
  return 0;
}