《C Primer Plus(第五版)中文版》第12章第1至8题

/*
 ============================================================================
1.不使用全局变量，重写12.4的程序
 ============================================================================
 */

#include <stdio.h>
void critic(int *p);
int main(void){
	int units;
	printf("How many pounds to a firkin of butter?
");
	scanf("%d",&units);
	while(units != 56){
		critic(&units);
	}
	printf("You must have looked it up!
");
    return 0;
}
void critic(int *p){
	printf("No luck chummy.Try again.
");
	scanf("%d",p);
}

/********************************************************************************
2.在美国通常以英里每加仑来计算油耗，在欧洲是以升每百公里来计算，下面是某程序的一部分，该
程序让用户选择一个模式（公制和美制），然后收集数据来计算油耗。
*********************************************************************************/
//p12-2b.c
#include <stdio.h>
#include "pe12-2a.h"
int main(void){
	int mode;
	printf("Enter 0 for metric mode,1 for US mode:");
	scanf("%d",&mode);
	while(mode >= 0){
		set_mode(mode);
		get_info();
		show_info();
		printf("Enter 0 for metric mode,1 for US mode:");
		printf("(-1 to quit):");
		scanf("%d",&mode);
	}
	printf("Done.
");
}

//p12-2a.h
void set_mode(int mode);
void get_info();
void show_info();

//pe12-2a.c
#include <stdio.h>
#include "pe12-2a.h"
static int modes;
static double distance;
static double fuel;

void set_mode(int mode){
	modes = mode;
}
void get_info(){
	if(modes == 0){
		printf("Enter distance traveled in kilometers:");
		scanf("%lf",&distance);
		printf("Enter fuel consumed in liters:");
		scanf("%lf",&fuel);
	}else if(modes == 1){
		printf("Enter distance traveled in miles:");
		scanf("%lf",&distance);
		printf("Enter fuel consumed in gallons:");
		scanf("%lf",&fuel);
	}else if(modes > 1){
		printf("Invalid mode specified,Mode 1(US) used.
");
		printf("Enter distance traveled in miles:");
		scanf("%lf",&distance);
		printf("Enter fuel consumed in gallons:");
		scanf("%lf",&fuel);
	}
}
void show_info(){
	if(modes == 0){
		printf("Fuel consumption is %.2f liters per 100 km.
",fuel/distance*100.0);
	}else if(modes >= 1){
		printf("Fuel consumption is %.2f miles per gallon.
",distance/fuel);
	}
}

/********************************************************************************
3.重新设计练习二，使用自动变量，程序提供相同的用户界面，也就是说，要提示用户输入模式等。
*********************************************************************************/
//p12-2b.c
#include <stdio.h>

void get_info(int modes,double *distance,double *fuel);
void show_info(int modes,double distance,double fuel);

int main(void){
	int mode;
	double distance;
	double fuel;
	printf("Enter 0 for metric mode,1 for US mode:");
	scanf("%d",&mode);
	while(mode >= 0){
		get_info(mode,&distance,&fuel);
		show_info(mode,distance,fuel);
		printf("Enter 0 for metric mode,1 for US mode:");
		printf("(-1 to quit):");
		scanf("%d",&mode);
	}
	printf("Done.
");
}

void get_info(int modes,double *distance,double *fuel){
	if(modes == 0){
		printf("Enter distance traveled in kilometers:");
		scanf("%lf",distance);
		printf("Enter fuel consumed in liters:");
		scanf("%lf",fuel);
	}else if(modes == 1){
		printf("Enter distance traveled in miles:");
		scanf("%lf",distance);
		printf("Enter fuel consumed in gallons:");
		scanf("%lf",fuel);
	}else if(modes > 1){
		printf("Invalid mode specified,Mode 1(US) used.
");
		printf("Enter distance traveled in miles:");
		scanf("%lf",distance);
		printf("Enter fuel consumed in gallons:");
		scanf("%lf",fuel);
	}
}
void show_info(int modes,double distance,double fuel){
	if(modes == 0){
		printf("Fuel consumption is %.2f liters per 100 km.
",fuel/distance*100.0);
	}else if(modes >= 1){
		printf("Fuel consumption is %.2f miles per gallon.
",distance/fuel);
	}
}

/********************************************************************************
3.编写一个函数，它返回函数自身被调用的次数，并在一个循环中测试
*********************************************************************************/
//p12-2b.c
#include <stdio.h>

void ta();

int main(void){
	for(int i = 0;i<5;i++)
		ta();
	printf("Done.
");
}

void ta(){
	static int a = 0;
	a++;
	printf("第%d次调用
",a);
}

/********************************************************************************
5.编写产生100个1到10范围的随机数，并且以降序排序。
*********************************************************************************/
//p12-2b.c
#include <stdio.h>
#include <stdlib.h>
void get100(int *p,int n);
void sort(int *p,int n);
int main(void){
	int a[100];
	get100(a,100);
	sort(a,100);
	for(int i = 0;i<100;i++){
		printf("%d: %d
",i+1,a[i]);
	}
	printf("
Done.
");
}

void get100(int *p,int n){
	for(int i = 0;i<100;i++){
		p[i] = (rand() % 10) + 1;
	}
}
void sort(int *p,int n){
	int temp;
	int i,j;
	for(i=0;i< 99;i++){
		for(j=i+1;j<100;j++){
			if(p[i] < p[j]){
				temp = p[j];
				p[j] = p[i];
				p[i] = temp;
			}
		}
	}
}

/********************************************************************************
6.编写产生1000个1到10范围的随机数,并统计每个数产生的次数
*********************************************************************************/
//p12-2b.c
#include <stdio.h>
#include <stdlib.h>
void get1000(int *p,int *s,int n,int m);
int main(void){
	int a[1000];
	int s[10];
	for(int i = 0;i<10;i++){
		s[i] = 0;
	}
	get1000(a,s,1000,10);
	for(int i=0;i<10;i++){
		printf("%d:%d
",i+1,s[i]);
	}
	printf("
Done.
");
}

void get1000(int *p,int *s,int n,int m){
	for(int i = 0;i<1000;i++){
		p[i] = (rand() % 10)+1;
		for(int j = 1;j<=m;j++){
			if(j == p[i]){
				s[j]++;
			}
		}
	}
}

/*
7.编写一个程序，该程序与我们在显示程序清单12.13输出之后所讨论的修改程序具有相同的表现，也就是说，输出应像下面这样：
Enter the number of sets,enter q to stop.
How many sides and how many dice?
Here are 18 sets of 3 6-sided throws：
11 7 10 11 10 15 13 9 12 13 11 9 8 12 8
16 7 9
Enter the number of sets,enter q to stop.
 */
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "diceroll.h"

int main(void){
	int dice, roll;
	int sides;
	int sets;

	srand((unsigned int) time(0));
	printf("Enter the number of sets,enter q to stop.
");
	while(scanf("%d",&sets) == 1 && sets > 0){
		printf("How many sides and how many dice?
");
		scanf("%d %d",&sides,&dice);
		printf("Here are %d sets of %d %d-sided throws：
",sets,dice,sides);
		for(int i = 0;i<sets;i++){
			roll = roll_n_dice(dice,sides);
			if(i % 15 == 0) printf("
");
			printf("%d ",roll);
		}
		printf("
Enter the number of sets,enter q to stop.
");
	}
	return 0;
}

/*
 * 8.下面是某程序的一部份，给出函数make_array()和show_array()的定义以使程序完整。函数make_array()接受两个参数。
 * 第一个是int数组的元素个数，第二个是要赋给每个元素的值。函数使用malloc()来创建一个适当大小的数组，把每个元素设定
 * 为指定的值，并返回一个数组指针，函数show_array()以8个数一行的格式显示数组的内容。
 *
 * pe12-8.c
 */

#include <stdio.h>
#include <stdlib.h>
int * make_array(int elem,int val);
void show_array(const int ar[],int n);

int main(void){
	int * pa;
	int size;
	int value;

	printf("Enter the number of elements: ");
	scanf("%d",&size);
	while(size > 0){
		printf("Enter the initialization value:");
		scanf("%d",&value);
		pa = make_array(size,value);
		if(pa){
			show_array(pa,size);
			free(pa);
		}
		printf("Enter the number of elements(<1 to quit)");
		scanf("%d",&size);
	}
	printf("Done.
");
}
int * make_array(int elem,int val){
	int * pd;
	pd = (int *) malloc(elem*sizeof(int));
	for(int i =0;i<elem;i++){
		pd[i] = val;
	}
	return pd;
}
void show_array(const int ar[],int n){
	for(int i = 0;i<n;i++){
		if(i % 8 == 0) printf("
");
		printf("%d ",ar[i]);
	}
	printf("
");
}