查找阵列的中位数

Question

#include<stdio.h> 
#include<stdlib.h> 
double median(int n, int arr[]) 
{ 
    int i, j, a; 
    for (i = 0; i < n; ++i) 
    { 
     for (j = i + 1; j < n; ++j) 
     { 
      if (arr[i] > arr[j]) 
      { 
       a = arr[i]; 
       arr[i] = arr[j]; 
       arr[j] = a; 
      } 
      if (arr[i] > arr[j]) 
      { 
       a = arr[i]; 
       arr[i] = arr[j]; 
       arr[j] = a; 
      } 
     } 
    } 
    if (n % 2 == 0) 
    { 
     return((arr[n/2] + arr[n/2 - 1])/2.0); 
    } 
    else { 
     return arr[n/2]; 
    } 
    for (i = 0; i < n; i++) 
    { 
     printf("%d\n", arr[i+1]); 
    } 
} 
int main() 
{ 
    int arr[100] = { 0 }; 
    int i, n, sum = 0; 
    printf("How many numbers would you like to enter?"); 
    scanf_s("%d", &n); 
    while (n > 100 || n < 0) 
    { 
     printf("Amount of numbers should be less than 0 and more than 100\n"); 
     scanf_s("%d", &n); 
    } 
    for (i = 0; i < n; i++) 
    { 
     scanf_s("%d", &arr[i + 1]); 
    } 
    printf("%f", median(n, arr)); 
    system("pause"); 
} 

看起来好像我的函数不会获得中值函数。该函数很好地排列数组，但找到中值是一个问题。只要函数找到中位数，它就会输出另一个值。任何类型的帮助将不胜感激。

Answer 1

我修改了一下你的代码，现在工作正常。您不需要median函数的内部for循环中的第二个if条件。我还删除了system("pause")命令，并在main函数中正确设置了阵列索引（将arr[i+1]更改为arr[i]）。我也删除了

while (n > 100 || n < 0) 
    { 
     printf("Amount of numbers should be less than 0 and more than 100\n"); 
     scanf_s("%d", &n); 
    } 

并将scanf_s更改为scanf。

修改后的代码：

#include<stdio.h> 
#include<stdlib.h> 
double median(int n, int arr[]) 
{ 
    int i, j, a; 
    for (i = 0; i < n; i++) 
    { 
     for (j = i + 1; j < n; j++) 
     { 
      if (arr[i] > arr[j]) 
      { 
       a = arr[i]; 
       arr[i] = arr[j]; 
       arr[j] = a; 
      } 

     } 
    } 

    for (i = 0; i < n; i++) 
    { 
     printf("%d\n", arr[i]); 
    } 
    if (n % 2 == 0) 
    { 
     return((arr[n/2] + arr[n/2 - 1])/2.0); 
    } 
    else { 
     return arr[n/2]; 
    } 

} 
int main() 
{ 
    int arr[100] = { 0 }; 
    int i, n; 
    printf("How many numbers would you like to enter?"); 
    scanf("%d", &n); 

    for (i = 0; i < n; i++) 
    { 
     scanf("%d", &arr[i]); 
    } 
    printf("%f", median(n, arr)); 

return 0; 
}