C语言程序设计(王立柱）第三章答案 指针和数组

#include<stdio.h>
int IndexOfMax(const int* p, int n);
void Selection(int* p, int n);
void OutputArray(const int* p, int n);
void SwapByAddress(int* a, int* b);
int main() {
  int a[10];
  int i;
  printf("Enter 10 integers:\n");
  for (i = 0; i < 10; i++) {
    scanf_s("%d", a + i);
  }
  Selection(a, 10);
  OutputArray(a, 10);
  return 0;
}
int IndexOfMax(const int* p, int n) {
  int i;
  int max = 0;
  for (i = 1; i < n; i++) {
    if (p[max] < p[i])
      max = i;
  }
  return max;
}
void Selection(int* p, int n) {
  int max;
  while (n > 1) {
    max = IndexOfMax(p, n);
    SwapByAddress(p+max, p+n-1);
    n--;
  }
}
void OutputArray(const int* p, int n) {
  for (int i = 0; i < n; i++)
    printf("%d\t", p[i]);
  printf("\n");
}
void SwapByAddress(int* a, int* b) {
  int temp;
  temp = *a;
  *a = *b;
  *b = temp;
}

#include<stdio.h>
int IndexOfMin(const int* p, int n);
void Selection(int* p, int n);
void OutputArray(const int* p, int n);
void SwapByAddress(int* a, int* b);
int main() {
  int a[10];
  int i;
  printf("Enter 10 integers:\n");
  for (i = 0; i < 10; i++) {
    scanf_s("%d", a + i);
  }
  Selection(a, 10);
  OutputArray(a, 10);
  return 0;
}
int IndexOfMin(const int* p, int n) {
  int i;
  int min = 0;
  for (i = 1; i < n; i++) {
    if (p[min] > p[i])
      min = i;
  }
  return min;
}
void Selection(int* p, int n) {
  int min;
  int temp = n;
  while (n > 1) {
    min = IndexOfMin(p + temp - n, n) + temp - n;
    //返回的min是后面部分数组的index，而不是原本数组的index
    SwapByAddress(p + min, p + temp - n);
    n--;
  }
}
void OutputArray(const int* p, int n) {
  for (int i = 0; i < n; i++)
    printf("%d\t", p[i]);
  printf("\n");
}
void SwapByAddress(int* a, int* b) {
  int temp;
  temp = *a;
  *a = *b;
  *b = temp;
}

#include<stdio.h>
void BubbleDown(int p[], int n);
void BubbleUp(int p[], int n);
void UpDown(int p[], int n);
void OutputArray(const int* p, int n) {
  for (int i = 0; i < n; i++)
    printf("%d\t", p[i]);
  printf("\n");
}
void SwapByAddress(int* a, int* b) {
  int temp;
  temp = *a;
  *a = *b;
  *b = temp;
}
int main() {
  const int num = 10;
  int a[10];
  printf("Enter %d integers:\n", num);
  for (int i = 0; i < num; i++) {
    scanf_s("%d", a + i);
  }
  //for (int i = 0; i < num; i++)
  //  BubbleUp(a + i, num - i);
  //for (int i = 0; i < num; i++)
  //  BubbleDown(a, num - i);
  int i = 0;
  int j = num;
  for (; i < j; i++, j--)
    UpDown(a + i, j - i);
  OutputArray(a, 10);
  return 0;
}
void BubbleDown(int p[], int n) {
  for (int i = 0; i < n - 1; i++) {
    if (p[i] > p[i + 1])
      SwapByAddress(p + i, p + i + 1);
  }
}
void BubbleUp(int p[], int n) {
  for (int i = n - 1; i >= 0; i--) {
    if (p[i] < p[i - 1])
      SwapByAddress(p + i, p + i - 1);
  }
}
void UpDown(int p[], int n) {
  BubbleUp(p, n);
  BubbleDown(p + 1, n - 1);
}

#include<stdio.h>
void Partition1(int p[], int n);
void Partition2(int p[], int n);
void OutputArray(const int* p, int n) {
  for (int i = 0; i < n; i++)
    printf("%d\t", p[i]);
  printf("\n");
}
void SwapByAddress(int* a, int* b) {
  int temp;
  temp = *a;
  *a = *b;
  *b = temp;
}
int main() {
  const int num = 10;
  int a[10];
  printf("Enter %d integers:\n", num);
  for (int i = 0; i < num; i++) {
    scanf_s("%d", a + i);
  }
  //支点为第一个元素
  Partition2(a, num);
  OutputArray(a, 10);
  return 0;
}
void Partition1(int p[], int n) {
  int* a;
  int* b;
  int* c;
  a = (int*)malloc(n * sizeof(int));
  b = (int*)malloc(n * sizeof(int));
  c = (int*)malloc(n * sizeof(int));
  int temp = p[0];
  for (int i = 1; i < n; i++) {
    if (temp >= p[i])
      a[i] = p[i], c[i] = 0;
    else
      b[i] = p[i], c[i] = 1;
  }
  int ai = 0;
  for (int i = 0; i < n; i++)
    if (c[i] == 0)
      p[ai++] = a[i];
  p[ai++] = temp;
  for (int i = 0; i < n; i++)
    if (c[i] == 1)
      p[ai++] = b[i];
  free(a);
  free(b);
  free(c);
}
void Partition2(int p[], int n) {
  int i = 0;
  int j = n - 1;
  while (i != j)
  {
    if (p[i] < p[i + 1])
    {
      SwapByAddress(p + i + 1, p + j);
      j--;
    }
    else
    {
      SwapByAddress(p + i + 1, p + i);
      i++;
    }
  }
}

#include<stdio.h>
#include<stdlib.h>
int main() {
  int n;
  printf("Enter an integer:\n");
  scanf_s("%d", &n);
  int* a;
  a = (int*)calloc(n + 1, sizeof(int));
  if (a == 0)
  {
    printf("allocation failure!\n");
    exit(1);
  }
  a[0] = a[1] = 1;
  for (int i = 2; i < n + 1; i++)
    if (a[i] == 0)
      for (int j = i + 1; j < n + 1; j++)
        if (j % i == 0)
          a[j] = 1;
  int hang = 0;
  for (int i = 0; i < n + 1; i++)
    if (a[i] == 0)
      if ((hang % 5 != 0) || (hang == 0))
      {
        printf("%d\t", i);
        hang++;
      }
      else
      {
        printf("\n");
        hang = 0;
      }
  free(a);
  return 0;
}

#include<stdio.h>
int indexofmax(const int* p, int n) {
  int i = 1;
  int max = 0;
  for (; i < n; i++)
    if (p[max] < p[i])
      max = i;
  return max;
}
int (*pofi)(const int*, int) = indexofmax;
void Selection(int* p, int n) {
  int max;
  int temp;
  while (n > 1) {
    max = pofi(p, n);
    temp = p[max];
    p[max] = p[n - 1];
    p[n - 1] = temp;
    n--;
  }
}
void (*pofs)(int* ,int) = Selection;
void OutputArray(const int* p, int n) {
  for (int i = 0; i < n; i++)
    printf("%d\t", p[i]);
  printf("\n");
}
int main() {
  int a[10];
  printf("Enter 10 integers:\n");
  for (int i = 0; i < 10; i++) {
    scanf_s("%d", a + i);
  }
  (*pofs)(a, 10);
  OutputArray(a, 10);
  return 0;
}