前面明明定义了i和j，后面为什么显示是未标识undeclared identifier

Question

#include<stdio.h>
#include<stdlib.h>
#include<assert.h>
#include<string.h>
#include<math.h>
#include<time.h>

void swap(int *a, int *b)
{
    int temp = *a;
    *a = *b;
    *b = temp;
}
void PrintArray(int* a, int n)
{
    int i = 0;
    for (; i < n - 1; ++i)
    {
        printf("%d ", a[i]);
    }
    printf("%d\n", a[i]);
}
//自小到大
void InsertSort(int* a, int n)//直接插入
{
    assert(a);
    int i,j;
    for (i = 1; i < n; i++)
    {
        if (a[i] < a[i - 1])
        {
            int temp = a[i];
            for (j = i - 1; j >= 0 && a[j] > temp; j--)
            {
                a[j + 1] = a[j];
            }
            a[j + 1] = temp;
        }
        printf("第%02d趟：", i);
        PrintArray(a, n);
    }
}

void BubbleSort(int* a, int n)//冒泡排序
{
    assert(a);

    int i,j=n,k = 1;
    int flag = 1;
    while (flag)
    {
        flag = 0;
        for (i = 1; i < j; i++)
        {
            if (a[i] < a[i - 1])
            {
                swap(&a[i], &a[i - 1]);
                flag = 1;
            }    
        }
        j--;
        if (flag)
        {
            printf("第%02d趟：", k++);
            PrintArray(a, n);
        }
    }
}
void SelectionSort(int* a, int n)//直接选择
{
    assert(a);

    int min, i, j;
    for (i = 0; i < n; i++)
    {
        min = i;
        for (j = i; j < n; j++)
        {
            if (a[j] < a[min])
                min = j;
        }
        swap(&a[i], &a[min]);
        printf("第%02d趟：", i+1);
        PrintArray(a, n);
    }
}

void QuickSort(int* a, int left, int right, int n)//快速排序
{
    assert(a);

    if (left < right)
    {
        static int k = 1;
        int i = left, j = right, x = a[left];
        while (i < j)
        {
            while (i < j && a[j] >= x) // 从右向左找第一个小于x的数
                j--;
            if (i < j)
                a[i++] = a[j];

            while (i < j && a[i] < x) // 从左向右找第一个大于等于x的数
                i++;
            if (i < j)
                a[j--] = a[i];
        }
        a[i] = x;
        printf("第%02d趟：", k++);
        PrintArray(a, n);
        QuickSort(a, left, i - 1, n); 
        QuickSort(a, i + 1, right, n);// 递归调用 
        
    }
}
void MergeSort(int*a, int left, int right, int* temp)//归并排序
{
    if (left >= right)
        return;

    int mid = (left + right) / 2;//left + ((right - left) >> 1);
    int begin1, begin2, end1, end2;
    int i = 0;

    MergeSort(a, left, mid, temp);
    MergeSort(a, mid + 1, right, temp);

    begin1 = left;
    end1 = mid;
    begin2 = mid + 1;
    end2 = right;
    i = left;
    while (begin1 <= end1 && begin2 <= end2)
    {
        if (a[begin1] > a[begin2])
        {
            temp[i++] = a[begin2++];
        }
        else
        {
            temp[i++] = a[begin1++];
        }
    }
    while (begin1 <= end1)
    {
        temp[i++] = a[begin1++];
    }
    while (begin2 <= end2)
    {
        temp[i++] = a[begin2++];
    }

    //memcpy(a + left, temp + left, end1-left);
    for (i--; i >= left; i--)
    {
        a[i] = temp[i];
    }
}

void table()
{
    printf("请选择对该组数据进行排序的方法:\n");
    printf("1.直接插入排序\n");
    printf("2.希尔排序\n");
    printf("3.冒泡排序\n");
    printf("4.快速排序排序\n");
    printf("5.简单选择排序\n");
    printf("6.归并排序\n");
    printf("0.退出\n");
}
int main()
{
    int a[10] = { 9,4,3,2,5,6,1,7,0,8 };
    srand((unsigned)time(NULL));
    int a[10];
    for (int i = 0; i < 10; i++)
        a[i] = rand() % 100;//生成随机数组
    int n = sizeof(a) / sizeof(a[0]);
    int* temp = (int*)malloc(sizeof(int)*n);
    int x = 0;
    printf("排序前数组：");
    PrintArray(a, n);
    table();
    scanf("%d", &x);
    printf("第00趟：");
    PrintArray(a, n);
    switch (x)
    {
    case 1:
        InsertSort(a, n);//直接插入
        break;

    case 3:
        BubbleSort(a, n);//冒泡排序
        break;

    case 5:
        SelectionSort(a, n);//直接选择
        break;
    case 6:
        MergeSort(a, 0, n-1, temp);//归并排序
        break;
    case 0:
        break;
    }
    printf("排序后数组：");
    PrintArray(a, n);
    system("pause");
    return 0;
}

Answer 1

中文引号?