初级C语言 函数 （二）

#include<stdio.h>
#include<string>
int main()
{
  char arr[] = "crush";
  int len = strlen(arr);
  printf("%d\n", len);
  return 0;
}

#include<stdio.h>
int Count_lenght(char*arr)
{
  int count = 0;
  while (*arr != '\0')
  {
  count++;
  arr++;
  }
  return count;
}
int main()
{
  char arr[] = "crush";
  int len = Count_lenght(arr);
  printf("%d\n", len);
  return 0;
}

#include<stdio.h>
int Count_lenght(char* arr)
{
  if (*arr != '\0')
  return 1 + Count_lenght(arr + 1);
  else
  return 0;
}
int main()
{
  char arr[] = "crush";
  int len = Count_lenght(arr);
  printf("%d\n", len);
  return 0;
}

#include<stdio.h>
int Fac(int i)
{
  if (i < 2)
  return 1;
  else
  return i * Fac(i - 1);
}
int main()
{
  int n = 0;
  scanf("%d", &n);
  int ret = Fac(n);
  printf("%d\n", ret);
  return 0;
}

#include<stdio.h>
int Fac(int n)
{
  int i = 0;
  int ret = 1;
  for (i = 1; i <= n; i++)
  {
  ret *= i;
  }
  return ret;
}
int main()
{
  int n = 0;
  scanf("%d", &n);
  int ret = Fac(n);
  printf("%d\n", ret);
  return 0;
}

#include<stdio.h>
int Fb(int i)
{
  if (i > 2)
  return Fb(i - 1) + Fb(i - 2);
  else
  return 1;
}
int main()
{
  int n = 0;
  int ret = 0;
  scanf("%d", &n);
  ret = Fb(n);
  printf("%d", ret);
  return 0;
}

#include<stdio.h>
int Fb(int n)
{
  int a = 1;
  int b = 1;
  int c = 1;
  while (n > 2)
  {
  c = a + b;
  a = b;
  b = c;
  n--;
  }
  return c;
}
int main()
{
  int n = 0;
  scanf("%d", &n);
  int ret = Fb(n);
  printf("ret = %d\n", ret);
  return 0;
}

#include<stdio.h>
int my_strlen(char* str)
{
  if ('\0' != *str)
  {
  return 1 + my_strlen(str + 1);
  }
  return 0;
}
void Reverse(char ch[])
{
  int left = 0;
  int right = my_strlen(ch) - 1;
  while (left < right)
  {
  char tmp = ch[left];
  ch[left] = ch[right];
  ch[right] = tmp;
  left++;
  right--;
  }
}
int main()
{
  char ch[] = "crush";
  printf("%s\n", ch);
  Reverse(ch);
  printf("%s\n", ch);
  return 0;
}

#include<stdio.h>
int my_strlen(char* str)
{
  if ('\0' != *str)
  {
  return 1 + my_strlen(str + 1);
  }
  return 0;
}
void Reverse(char* str)
{
  //1.先保存第一个字符
  char tmp = *str;
  int len = my_strlen(str);
  //2.将最后一个字符存放在第一个字符的位置
  *str = *(str + len - 1);
  //3.将最后一个字符设置为\0，以便字符串长度的计算
  *(str + len - 1) = '\0';
  //4.进行中间字符串的逆序（除去第一个和最后一个字符）
  if (my_strlen(str + 1) > 1)
  {
  Reverse(str + 1);
  }
  //5.将第一个字符存放在最后一个字符的位置
  *(str + len - 1) = tmp;
}
int main()
{
  char ch[] = "crush";
  printf("%s\n", ch);
  Reverse(ch);
  printf("%s\n", ch);
  return 0;
}

#include<stdio.h>
int my_strlen(char* str)
{
  if ('\0' != *str)
  {
  return 1 + my_strlen(str + 1);
  }
  return 0;
}
void Reverse(char ch[], int left, int right)
{
  if (left < right)
  {
  char tmp = ch[left];
  ch[left] = ch[right];
  ch[right] = tmp;
  Reverse(ch, left + 1, right - 1);
  }
}
int main()
{
  char ch[] = "crush";
  printf("%s\n", ch);
  int left = 0;
  int right = my_strlen(ch) - 1;
  Reverse(ch,left,right);
  printf("%s\n", ch);
  return 0;
}