成信大2021自动化专业-平时自主学习-C语言改错题解题参考-整理第08页

原创 于 2021-12-21 10:47:20 发布 · 2.1k 阅读 · 5 ·
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#c语言 #自动化 #开发语言

文章目录

第08页

题面如下：

在这里插入图片描述

题解如下：

D1054.c

原文件

#include <stdio.h>

int main(void)
{ 
	unsigned long int number, num1, num2, mask;
	int i;
	char str[33];
	
	printf("Please input num1 and num2 : ");
	scanf("%lu %lu", &num1, &num2);
	
	/*********Found************/
	mask = __________________;
	number = num1 ^ num2;
	for(i=0; i<32; i++)
	{ 
		/*********Found************/
		str[i] = __________________;
		mask >>= 1;
	}
	str[32] = '\0';
	printf("%lu ^ %lu = %s\n", num1, num2, str);
	
	return 0;
}

改后文件

#include <stdio.h>

int main(void)
{ 
	unsigned long int number, num1, num2, mask;
	int i;
	char str[33];
	
	printf("Please input num1 and num2 : ");
	scanf("%lu %lu", &num1, &num2);
	
	/*********Found************/
	mask = 1<<31;
	number = num1 ^ num2;
	for(i=0; i<32; i++)
	{ 
		/*********Found************/
		str[i] = number&mask ?'1':'0';
		mask >>= 1;
	}
	str[32] = '\0';
	printf("%lu ^ %lu = %s\n", num1, num2, str);
	
	return 0;
}

考查要点：

  1. 位运算，移位，要注意编译器给出的相应的数据类型的内存长度
  2. 从高位到低位，依次用与的方式取出该位上的1或是0，然后存入数组中
  3. 最后将字符数组做成字符串，即补结束符号

D1055.c

原文件

#include<stdio.h>  
#include<malloc.h>  

#define N 13  
#define LEN sizeof(struct person)  

int main(void)
{  
	int i, count;
	struct person
	{
		int number;
		/*********Found************/
		___________________________;
	} *head, *p1, *p2;

	head = p2 = NULL;
	for (i=1; i<=N; i++)
	{  
		p1 = (struct person *)malloc(LEN);
		p1->number = i;
		if (NULL == head)
		{
			/*********Found************/
			___________________________;
		}
		else
		{
			p2->next = p1; 
		}
		p2 = p1;
	}
	p2->next = head;

	printf("the sequence out of the circle is:\n");
	for (count=1; count<N; count++)
	{
		i = 1;
		while (i != 3)
		{
			p1 = head;
			/*********Found************/
			___________________________;
			i++;
		}
		p2 = head;
		printf("%3d ", p2->number);
		p1->next = head = p2->next;
		/*********Found************/
		___________________________;
	}
	printf("\nThe betrayer of them is:%3d\n", head->number);
	
	return 0;
}

改后文件

#include<stdio.h>  
#include<malloc.h>  

#define N 13  
#define LEN sizeof(struct person)  

int main(void)
{  
	int i, count;
	struct person
	{
		int number;
		/*********Found************/
		struct person * next;
	} *head, *p1, *p2;

	head = p2 = NULL;
	for (i=1; i<=N; i++)
	{  
		p1 = (struct person *)malloc(LEN);
		p1->number = i;
		if (NULL == head)
		{
			/*********Found************/
			head = p1;
		}
		else
		{
			p2->next = p1; 
		}
		p2 = p1;
	}
	p2->next = head;

	printf("the sequence out of the circle is:\n");
	for (count=1; count<N; count++)
	{
		i = 1;
		while (i != 3)
		{
			p1 = head;
			/*********Found************/
			head = head->next;
			i++;
		}
		p2 = head;
		printf("%3d ", p2->number);
		p1->next = head = p2->next;
		/*********Found************/
		free(p2);
	}
	printf("\nThe betrayer of them is:%3d\n", head->number);
	
	return 0;
}

考查要点：

  1. 约瑟夫环问题
  2. 节点定义中，需要有指针域
  3. 首节点，用头指针来指
  4. 用head指针后移的方式完成出圈
  5. 出圈后，要记得归还内存

D1056.c

原文件

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[])
{
    FILE *fp;
    char str[100], substr[100];
    int count = 0;
	
    if (argc != 2)
    {
		printf("error");
		exit(0);
    }

	/*********Found************/
	fp = fopen(__________, "r");
	if (NULL == fp)
	{
		printf("file open error\n");         
		exit(0);
	}
	
	printf("Please input the string : ");
	gets(substr);
	
	while (!feof(fp))
	{
		count++;
		str[0] = '\0';
		/*********Found************/
		___________________________;
		if (strstr(str, substr))
		{
			printf("Line%d : ", count);
			puts(str);
		}
	}
	
	/*********Found************/
	___________________________;
	return 0;
}

改后文件

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char *argv[])
{
    FILE *fp;
    char str[100], substr[100];
    int count = 0;
	
    if (argc != 2)
    {
		printf("error");
		exit(0);
    }

	/*********Found************/
	fp = fopen(argv[1], "r");
	if (NULL == fp)
	{
		printf("file open error\n");         
		exit(0);
	}
	
	printf("Please input the string : ");
	gets(substr);
	
	while (!feof(fp))
	{
		count++;
		str[0] = '\0';
		/*********Found************/
		fgets(str,100,fp);
		if (strstr(str, substr))
		{
			printf("Line%d : ", count);
			puts(str);
		}
	}
	
	/*********Found************/
	fclose(fp);
	return 0;
}

考查要点：

  1. 文件打开后要记得关闭
  2. fgets的三个参数要清楚：写内存缓区冲指针，大小，文件指针

D1057.c

原文件

#include <stdio.h>

int main(void)
{
	float numA, numB, *ptr;

	numA = 4.5;
	numB = 6.8f;
	/*********Found************/
	ptr = numB;
	/*********Found************/
	printf("numA=%f, numB=%f\n", numA, ptr);

	return 0;
}

改后文件

#include <stdio.h>

int main(void)
{
	float numA, numB, *ptr;

	numA = 4.5;
	numB = 6.8f;
	/*********Found************/
	ptr = &numB;
	/*********Found************/
	printf("numA=%f, numB=%f\n", numA, *ptr);

	return 0;
}

考查要点：

  1. 指针和变量的关系
  2. 取值和取址

D1058.c

原文件

#include <stdio.h>

int main(void)
{ 
	struct student
	{
		int num;
		char name[10];
		float score[3];
	} stu1 = {2012,  "WuHua",  {75.4f, 80, 92}}; 
	struct student *ptr;
	
	/*********Found************/
	ptr = stu1;
	/*********Found************/
	printf("%s\n", ptr.name);
	
	return 0;
}

改后文件

#include <stdio.h>

int main(void)
{ 
	struct student
	{
		int num;
		char name[10];
		float score[3];
	} stu1 = {2012,  "WuHua",  {75.4f, 80, 92}}; 
	struct student *ptr;
	
	/*********Found************/
	ptr = &stu1;
	/*********Found************/
	printf("%s\n", ptr->name);
	
	return 0;
}

考查要点：

  1. 指针和结构
  2. 用指针的方式访问结构成员：指向

D1059.c

原文件

#include <stdio.h>

int main(void)
{ 
	int *ptr, i, arrA[10];

	/*********Found************/
	___________________________;
	for (i=0; i<10; i++)
	{
		scanf("%d", ptr++);
	}
	printf("\n");
	/*********Found************/
	___________________________;
	for(i=0;  i<10;  i++, ptr++)
	{
		printf("%d ",*ptr);
	}
	printf("\n");
	
	return 0;
}

改后文件

#include <stdio.h>

int main(void)
{ 
	int *ptr, i, arrA[10];

	/*********Found************/
	ptr = arrA;
	for (i=0; i<10; i++)
	{
		scanf("%d", ptr++);
	}
	printf("\n");
	/*********Found************/
	ptr = arrA;
	for(i=0;  i<10;  i++, ptr++)
	{
		printf("%d ",*ptr);
	}
	printf("\n");
	
	return 0;
}

考查要点：

  1. 指针和数组的关系
  2. 用指针移动和遍历数组元素

D1060.c

原文件

#include <stdio.h>

int main(void)
{ 
	struct student
	{
		int num;
		char name[10];
	} stu[3], *ptr;
	int i;

	for (i=0; i<3; i++)
	{
		scanf("%d,%s", &stu[i].num, stu[i].name);
	}
	/*********Found************/
	for (ptr=stu; __________; _________)
	{
		printf("%d, %s\n", ptr->num, ptr->name);
	}

	return 0;
}

改后文件

#include <stdio.h>

int main(void)
{ 
	struct student
	{
		int num;
		char name[10];
	} stu[3], *ptr;
	int i;

	for (i=0; i<3; i++)
	{
		scanf("%d,%s", &stu[i].num, stu[i].name);
	}
	/*********Found************/
	for (ptr=stu; ptr<stu+3; ptr++)
	{
		printf("%d, %s\n", ptr->num, ptr->name);
	}

	return 0;
}

考查要点：

  1. 结构体基础知识
  2. 指针基础知识
  3. 数组基础知识
  4. 使用指针来遍历结构体数组

D1061.c

原文件

#include <stdlib.h>
#include <stdio.h>

#define LEN sizeof(struct student)

struct student
{
	int num;
	char name[20];
	struct student *next;
};

struct student *creat(void);
void display(struct student *head);

int main(void)
{
	struct student * head;
	
	head = creat();
	display(head);
	
	return 0;
}

struct student *creat(void)
{
	struct student *p1, *p2, *head=NULL;
	int num;
	
	printf("请输入学号及姓名(学号输入为0时表示停止)：\n");
	while (1)
	{
		scanf("%d", &num);
		if (0 == num) 
		{
			break;
		}
		
		p1 = (struct student *)malloc(LEN);
		p1->num = num;
		scanf("%s",  p1->name);
		if (NULL == head)
		{
			head = p1;
		}
		else
		{
			
			p2->next = p1;
		}
		/*********Found************/
		___________________________;
	}
	
	if (head != NULL)
	{
		p2->next = NULL;
	}

	/*********Found************/
	___________________________;
}

void display(struct student *head)
{
	struct student *p1;

	p1 = head;
	while (p1 != NULL)
	{
		printf("%d, %s ", p1->num, p1->name);
		p1 = p1->next;
	}
}

改后文件

#include <stdlib.h>
#include <stdio.h>

#define LEN sizeof(struct student)

struct student
{
	int num;
	char name[20];
	struct student *next;
};

struct student *creat(void);
void display(struct student *head);

int main(void)
{
	struct student * head;
	
	head = creat();
	display(head);
	
	return 0;
}

struct student *creat(void)
{
	struct student *p1, *p2, *head=NULL;
	int num;
	
	printf("请输入学号及姓名(学号输入为0时表示停止)：\n");
	while (1)
	{
		scanf("%d", &num);
		if (0 == num) 
		{
			break;
		}
		
		p1 = (struct student *)malloc(LEN);
		p1->num = num;
		scanf("%s",  p1->name);
		if (NULL == head)
		{
			head = p1;
		}
		else
		{
			
			p2->next = p1;
		}
		/*********Found************/
		p2 = p1;
	}
	
	if (head != NULL)
	{
		p2->next = NULL;
	}

	/*********Found************/
	return head;
}

void display(struct student *head)
{
	struct student *p1;

	p1 = head;
	while (p1 != NULL)
	{
		printf("%d, %s ", p1->num, p1->name);
		p1 = p1->next;
	}
}

考查要点：

  1. 结构
  2. 链表
  3. 遍历链表节点

D1062.c

原文件

#include <stdio.h>

void findmax(int (*pArr)[4], int *pmax, int m, int n);

int main(void)
{ 
	int arr[3][4], *pa, max[3], i;
	
	printf("input 12 elements : \n");
	pa = arr[0];
	for (i=0; i<12; i++)
	{
		scanf("%d", pa++);
	}
	
	findmax(arr, max, 3, 4);
	for (i=0; i<3; i++)
	{
		printf("line %d's max = %d\n", i, max[i]);
	}
	
	return 0;
}

void findmax(int (*pArr)[4], int *pmax, int m, int n)
{
	int i, j;
	
	for (i=0;  i<m;  i++, pmax++)
	{
		/*********Found************/
		*pmax = ___________________;
		for (j=1; j<n; j++)
		{
			/*********Found************/
			if (_______________ > *pmax)
			{
				/*********Found************/
				*pmax = ___________________;
			}
		}
	}
}

改后文件

#include <stdio.h>

void findmax(int (*pArr)[4], int *pmax, int m, int n);

int main(void)
{ 
	int arr[3][4], *pa, max[3], i;
	
	printf("input 12 elements : \n");
	pa = arr[0];
	for (i=0; i<12; i++)
	{
		scanf("%d", pa++);
	}
	
	findmax(arr, max, 3, 4);
	for (i=0; i<3; i++)
	{
		printf("line %d's max = %d\n", i, max[i]);
	}
	
	return 0;
}

void findmax(int (*pArr)[4], int *pmax, int m, int n)
{
	int i, j;
	
	for (i=0;  i<m;  i++, pmax++)
	{
		/*********Found************/
		*pmax = *(*(pArr+i));
		for (j=1; j<n; j++)
		{
			/*********Found************/
			if (*(*(pArr+i)+j) > *pmax)
			{
				/*********Found************/
				*pmax = *(*(pArr+i)+j);
			}
		}
	}
}

考查要点：

  1. 函数
  2. 指针
  3. 二维数组
  4. 行指针指向二级数组

D1063.c

原文件

#include <stdio.h>

void change(int *p1, int *p2);
/*********Found************/
______sort(int *pArr, int n);

int main( )
{
	int arr[20], *pa, i, n;
	
	printf("Please input the number n = ");
	scanf("%d", &n);
	printf("Please input the array elements : ");
	for (i=0, pa=arr;  i<n;  i++)
	{
		scanf("%d", pa++); 
	}

	/*********Found************/
	___________________________;
	printf("\n output : \n");
	for (i=0; i<n; i++)
	{
		printf("%d   ", *(pa + i));
	}
	printf("\n");
	
	return 0;   
}

void change(int *p1, int *p2)
{
	int tmp;
	
	tmp = *p1;
	*p1 = *p2;
	*p2 = tmp;
}

/*********Found************/
______sort(int *pArr, int n)
{
	int i, *pa;
	
	for (i=n-1; i>0; i--)
	{
		for (pa=pArr; pa<pArr+i; pa++)
		{
			if (*pa > *(pa+1))
			{
				change(pa, pa+1);
			}
		}
	}
	
	/*********Found************/
	___________________________;
}

改后文件

#include <stdio.h>

void change(int *p1, int *p2);
/*********Found************/
int * sort(int *pArr, int n);

int main( )
{
	int arr[20], *pa, i, n;
	
	printf("Please input the number n = ");
	scanf("%d", &n);
	printf("Please input the array elements : ");
	for (i=0, pa=arr;  i<n;  i++)
	{
		scanf("%d", pa++); 
	}

	/*********Found************/
	pa = sort(arr, n);
	printf("\n output : \n");
	for (i=0; i<n; i++)
	{
		printf("%d   ", *(pa + i));
	}
	printf("\n");
	
	return 0;   
}

void change(int *p1, int *p2)
{
	int tmp;
	
	tmp = *p1;
	*p1 = *p2;
	*p2 = tmp;
}

/*********Found************/
int * sort(int *pArr, int n)
{
	int i, *pa;
	
	for (i=n-1; i>0; i--)
	{
		for (pa=pArr; pa<pArr+i; pa++)
		{
			if (*pa > *(pa+1))
			{
				change(pa, pa+1);
			}
		}
	}
	
	/*********Found************/
	return pArr ;
}

考查要点：

  1. 函数
  2. 返回地址的情况，即指针函数
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