[C++知识库]CPrimer Plus第6版第十六章编程练习答案(C语言)(自学记录)

第一题

将后面的头文件全部放入第一题中

#pragma once
//第一题

#ifdef SIXTH_2
#include <stdio.h>
#define TIAOHE(X,Y) (1/((1/(X)+1/(Y))/2))
#endif // SIXTH_2

#ifdef SIXTH_3		//输入向量的模和角度，显示x轴和y轴的坐标
#include <stdio.h>
#include <math.h>
#define PI 3.14159
#define Radian(A) ((A)*PI/180)		//将角度转换为弧度
#define CoordinateX(R,Y) ((R)*cos(Radian(Y)))			//X轴坐标
#define CoordinateY(R,Y) ((R)*sin(Radian(Y)))			//y轴坐标
typedef struct{
	double novecter;
	double angle;
}PolarCoor;
typedef struct{
	double x;
	double y;
}Coordinate;
extern Coordinate Angle_Coor(PolarCoor therr);
#endif // SIXTH_3

#ifdef SIXTH_4
#include <stdio.h>
#include <time.h>
extern void time_yc(const double tim);
#endif // SIXTH_4

#ifdef SIXTH_5
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <stdbool.h>
#include <string.h>
#define SHILI 30
#define RAND(X,Y) (rand()%((Y)-(X)+1)+(X))			//输入选择的随机数的最大值和最小值
extern void rand_num_one(const int* name_name, int name_time, int name_num);
#endif // SIXTH_5

#ifdef SIXTH_6
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define NUM 40
#define SLEN 5
typedef struct {
	char first[NUM];
	char last[NUM];
}names;
void showarray(const names ar[], int n);
int mycomp(const void* p1, const void* p2);
#endif // SIXTH_6

#ifdef SIXTH_7
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
void show_array(const double ar[], int n);
double* new_d_array(int n, ...);
#endif // SIXTH_7

#ifdef SIXTH_2
#define TIAOHE(X,Y) (1/((1/(X)+1/(Y))/2))
#endif // SIXTH_2

第二题

//第二题
#define SIXTH_2
#include "sixth_one.h"
int main(void)
{
	double x, y;
	double sum;
	printf("请输入两个数:");
	scanf_s("%lf%lf",&x,&y);
	sum=TIAOHE(x, y);
	printf("\nx为:%.6lf,y为:%.6lf,调和平均数为:%.6lf\n", x, y, sum);
	return 0;
}

第三题

//第三题
#define SIXTH_3
#include "sixth_one.h"
int main(void)
{
	PolarCoor example_input;
	Coordinate example_output;
	printf("Hello,please enter norm of vector(请输入向量的模):");
	scanf_s("%lf", &example_input.novecter);
	printf("Please enter angle(请输入角度):");
	scanf_s("%lf", &example_input.angle);
	puts("您已经输入极坐标信息，请稍等:");
	example_output=Angle_Coor(example_input);
	printf("您输入的向量长度为%.2lf,您输入的角度为%.2lf\n", example_input.novecter, example_input.angle);
	printf("对应的x坐标为%.2lf,对应的y坐标为%.2lf.\n", example_output.x, example_output.y);
	printf("完整表示为(%.2lf,%.2lf)", example_output.x, example_output.y);
	return 0;
}
Coordinate Angle_Coor(PolarCoor three)
{
	Coordinate good;
	good.x = CoordinateX(three.novecter, three.angle);
	good.y = CoordinateY(three.novecter, three.angle);
	return good;
}

第四题

//第四题
#define SIXTH_4
#include "sixth_one.h"
int main(void)
{
	double ceshi;
	printf("请输入一个数(小于0或者非数字结束):");
	while (scanf_s("%lf", &ceshi) == 1)
	{
		time_yc(ceshi);
		printf("请输入一个数,<0或者非数字结束:");
	}
	puts("Done!");
	return 0;
}
void time_yc(const double tim)
{
	
	clock_t start = clock();
	clock_t end = clock();
	while (((double)((double)end - (double)start) / CLOCKS_PER_SEC) < tim)
	{
		end = clock();
	}
	printf("时间延迟数为%g\n,时间开始数为%ld,时间结束数为%ld\n", ((double)((double)end - (double)start) / CLOCKS_PER_SEC),start,end);
}

第五题

//第五题
#define SIXTH_5
#include "sixth_one.h"
int main(void)
{
	int a[SHILI];
	int i;
	int nno;
	srand((unsigned)time(0));
	for (i = 0; i < SHILI; i++)
	{
		a[i] = rand();
	}
	printf("请输入要抽几次奖:");
	while (scanf_s("%d", &nno) == 1)
	{
		printf("输出抽奖的值:\n");
		rand_num_one(a, SHILI, nno);
		printf("\n请输入要抽几次奖(输入q结束	):");
	}
	scanf_s("%d", &nno);
	
	return 0;
}
void rand_num_one(const int* name_name, int name_time, int name_num)
{
	int i;
	int copy;
	int* r_bool;
	r_bool = (int *)malloc(sizeof(int) * name_time);
	memset(r_bool, 0, sizeof(int) * name_time);
	srand((unsigned)time(0));
	for (i = 0; i < name_num; i++)
	{
		copy=RAND(0, name_time);
		printf("copy:%d,", copy);
		if (r_bool[copy] == 0)
		{
			r_bool[copy] = 1;
			printf("%-8d\n", name_name[copy]);
		}
	}
	free(r_bool);
}

第六题

//第六题
#define SIXTH_6
#include "sixth_one.h"
int main(void)
{
	names vals[SLEN] = {
		{"MARK","ONE"},
		{"HARK","TWO"},
		{"CHAK","THREE"},
		{"GHAK","FOUR"},
		{"TACK","FIVE"}
	};
	puts("打印排序前数据:");
	showarray(vals, SLEN);
	qsort(vals, SLEN, sizeof(names), mycomp);
	puts("\n打印排序后数据:");
	showarray(vals, SLEN);
	return 0;
}
void showarray(const names ar[],int n)
{
	int index;
	for (index = 0; index < n; index++)
		printf("%40s,%40s\n", ar[index].first, ar[index].last);
} 
/*按从小到大的顺序排序*/
int mycomp(const void* p1, const void* p2)
{
	/*要使用指向double的指针来访问这两个值*/
	const names* a1 = (const names*)p1;
	const names* a2 = (const names*)p2;
	if ((strcmp(a1->first, a2->first)) < 0)			//此处
		return -1;
	else if (strcmp(a1->first, a2->first) == 0)
	{
		if (strcmp(a1->last, a2->last) < 0)
			return -1;
		else if (strcmp(a1->last, a2->last) == 0)
			return 0;
		else
			return 1;
	}
	else
		return 1;
}

第七题

//第七题
#define SIXTH_7
#include "sixth_one.h"
int main(void)
{
	double* p1;
	double* p2;
	p1 = new_d_array(5, 1.2, 2.3, 3.4, 4.5, 5.6);
	p2 = new_d_array(4, 100.0, 20.00, 8.08, -1890.0);
	show_array(p1, 5);
	show_array(p2, 4);
	free(p1);
	free(p2);
	return 0;
}

double* new_d_array(int n, ...)
{
	int x;		//计数器
	va_list ap;
	double* pe = NULL;
	va_start(ap, n);
	pe = (double*)malloc(n * sizeof(double));
	if (NULL == pe)
		exit(EXIT_FAILURE);
	for (x = 0; x < n; x++)
	{
		pe[x] = (double)va_arg(ap, double);
	}
	va_end(ap);
	return pe;
}

void show_array(const double ar[], int n)
{
	int x;
	printf("共%d个数字", n);
	for (x = 0; x < n; x++)
	{
		printf("%6.2lf ", ar[x]);
		if (x % 5 == 4)
			putchar('\n');
	}
	putchar('\n');
}