例10-1 有序表的增删查操作。首先输入一个无重复元素的、从小到大排列的有序表,并在屏幕上显示以下菜单(编号和选项),用户可以反复对该有序表进行插入、删除和查找操作,也可以选择结束。当用户输入编号1-3和相关参数时,将分别对该有序表进行插入、删除和查找操作,输入其他编号,则结束操作。
[1] Insert
[2] Delete
[3] Query
[Other option] End
#include<stdio.h>
#define MAXN 100
int Count=0;
void select(int a[],int option,int value);
void input_array(int a[]);
void print_array(int a[]);
void insert(int a[],int value);
void remov(int a[],int value);
void query(int a[],int value);
int main(void)
{
int option,value,a[MAXN];
input_array(a);
printf("[1] Insert\n");
printf("[2] Delete\n");
printf("[3] Query\n");
printf("[Other option] End\n");
while(1)
{
printf("Input option:");
scanf("%d",&option);
if(option<1 || option>3)
{
break;
}
printf("Input an element:");
scanf("%d",&value);
select(a,option,value);
printf("\n");
}
printf("Thanks.");
return 0;
}
void print_array(int a[])
{
int i;
printf("The ordered array a is:");
for(i=0;i<Count;i++)
{
if(i==Count-1)
{
printf("%d",a[i]);
}
else
{
printf("%d ",a[i]);
}
}
}
void delet(int a[ ],int value)
{
int i,index=-1;
for(i=0;i<Count;i++)
{
if(value==a[i])
{
index=i;
break;
}
}
if(index==-1)
{
printf("Failed to find the data,deletion failed.");
}
else
{
for(i=index;i<Count-1;i++)
{
a[i]=a[i+1];
}
}
Count--;
print_array(a);
}
void select(int a[],int option,int value)
{
switch(option)
{
case 1:
insert(a,value);
break;
case 2:
delet(a,value);
break;
case 3:
query(a,value);
break;
}
}
void input_array(int a[])
{
int i;
printf("Input the number of array elements:");
scanf("%d",&Count);
printf("Input an ordered array element:");
for(i=0;i<Count;i++)
{
scanf("%d",&a[i]);
}
}
void insert(int a[],int value)
{
int i,j;
for(i=0;i<Count;i++)
{
if(value<a[i])
{
break;
}
}
for(j=Count-1;j>=i;j--)
{
a[j+1]=a[j];
}
a[i]=value;
Count++;
print_array(a);
}
void query(int a[],int value)
{
int mid,left=0,right=Count-1;
while(left<=right)
{
mid=(left+right)/2;
if(value==a[mid])
{
printf("The index is:%d",mid);
return;
}
else if(value<a[mid])
{
right=mid-1;
}
else
{
left=mid+1;
}
}
printf("This element does not exist.");
}
例10-2 用递归函数实现求n!。
·#include<stdio.h>
double fact(int n);
int main(void)
{
int n;
scanf("%d",&n);
printf("%f",fact(n));
return 0;
}
double fact(int n)
{
double result;
if(n==1 || n==0)
{
result=1;
}
else
{
result=n*fact(n-1);
}
return result;
}
例10-3 定义函数gcd(m,n),用递归法求m和n的最大公约数。
#include<stdio.h>
int gcd(int m,int n)
{
if(m%n==0)
{
return n;
}
else
{
return gcd(n,m%n);
}
}
int main(void)
{
int a,b,gys;
printf("Enter a,b:");
scanf("%d%d",&a,&b);
gys=gcd(a,b);
printf("%d\n",gys);
return 0;
}
例10-4 编写递归函数reverse(int n)实现将整数n逆序输出。
#include<stdio.h>
void reverse(int num)
{
if(num<=9)
printf("%d",num);
else
{
printf("%d",num%10);
reverse(num/10);
}
}
int main(void)
{
int a;
printf("Enter a:");
scanf("%d",&a);
reverse(a);
return 0;
}
例10-5 汉诺(Hanoi)塔问题。要求用程序模拟盘子搬动过程,并输出搬动步骤。
#include<stdio.h>
void hanoi(int n,char a,char b,char c);
int main(void)
{
int n;
printf("input the number of disk:");
scanf("%d",&n);
printf("the steps for %d disk are:\n",n);
hanoi(n,'a','b','c');
return 0;
}
void hanoi(int n,char a,char b,char c)
{
if(n==1)
{
printf("%c --> %c\n",a,b);
}
else
{
hanoi(n-1,a,c,b);
printf("%c --> %c\n",a,b);
hanoi(n-1,c,b,a);
}
}
例10-6 分治法求解金块问题:老板有一袋金块(共n块,2),两名最优秀的雇员每人可以得到其中一块,排名第一的得到最重的金块,排名第二的则得到袋子中最轻的金块。输入n及n个整数,用分治法求出最重金块和最轻金块。
/*分治法求a[m]-a[n]中最大值的递归函数*/
int max(int a[],int m,int n)
{
int k,u,v;
if(m==n) //数组a中只有1个元素,返回最大值a[m]
{
return a[m];
}
k=(m+n)/2; //计算中间元素的下标
u=max(a,m,k); //递归调用函数max(),在a[m]-a[k]中找出最大值赋给u
v=max(a,k+1,n); //同上
return(u>v)?u:v;
}
int min(int b[],int m,int n)
{
int k,u,v;
if(m==n)
{
return b[m];
}
k=(m+n)/2;
u=min(b,m,k);
v=min(b,k+1,n);
return(u<v)?u:v;
}
int main(void)
{
int n;
printf("Enter n:");
scanf("%d",&n);
int a[n];
int i;
for(i=0;i<n;i++)
{
scanf("%d",&a[i]);
}
int best,better;
best=max(a,0,n-1);
better=min(a,0,n-1);
printf("%d %d\n",best,better);
return 0;
}
例10-7 欧美国家长度使用英制单位,如英里、英尺、英寸等,其中1英里=1609米,1英尺=30.48厘米,1英寸=2.54厘米。请编写程序将输入的英里转换成米,英尺和英寸转换成厘米。
#include<stdio.h>
#define Mile_to_meter 1609
#define Foot_to_centimeter 30.48
#define Inch_to_centimeter 2.54
int main(void)
{
float foot,inch,mile;
printf("Input mile,foot and inch:");
scanf("%f%f%f",&mile,&foot,&inch);
printf("%f miles=%f meters\n",mile,mile*Mile_to_meter);
printf("%f feet=%f centimeters\n",foot,foot*Foot_to_centimeter);
printf("%f inches=%f centimeters\n",inch,inch*Inch_to_centimeter);
return 0;
}
例10-8 简单的带参数的宏定义。
#include<stdio.h>
#define MAX(a,b) a>b?a:b
#define SQR(x) x*x
int main(void)
{
int x,y;
scanf("%d%d",&x,&y);
x=MAX(x,y);
y=SQR(x);
printf("%d %d\n",x,y);
return 0;
}
例10-9 将例10-7中长度转换的宏定义成头文件length.h,并写出主函数文件。
#include<stdio.h>
#define Mile_to_meter 1609
#define Foot_to_centimeter 30.48
#define Inch_to_centimeter 2.54
int main(void)
{
float foot,inch,mile;
printf("Input mile,foot and inch:");
scanf("%f%f%f",&mile,&foot,&inch);
printf("%f miles=%f meters\n",mile,mile*Mile_to_meter);
printf("%f feet=%f centimeters\n",foot,foot*Foot_to_centimeter);
printf("%f inches=%f centimeters\n",inch,inch*Inch_to_centimeter);
return 0;
}
length.h头文件如下:
#define Mile_to_meter 1609
#define Foot_to_centimeter 30.48
#define Inch_to_centimeter 2.54
例10-10 请在例9-1、例9-2和例9-3的基础上,分模块设计一个学生信息库系统。该系统包含学生基本信息的建立和输出、计算学生平均成绩、按照学生的平均成绩排序以及查询、修改学生的成绩等功能。
//主函数程序文件student_system.c
#include "student.h"
#include "input_output.c" //用文件包含连接各程序文件模块
#include "computing.c"
#include "update.c"
#include "search.c"
int Count=0; //全局变量,记录当前学生总数
int main(void)
{
struct student students[MaxSize]; //定义学生信息结构数组
new_student(students); //输入学生信息结构数组
output_student(students); //显示输入的学生信息结构数组
average(students); //计算每一个学生的平均成绩
sort(students); //按学生的平均成绩排序
output_student(students); //显示排序后的结构数组
modify(students); //修改指定输入的学生信息
output_student(students); //显示修改后的结构数组
return 0;
}
#include <stdio.h>
#include <string.h>
#define MaxSize 50
struct student{
int num;
char name[10];
int computer,english,math;
double average;
};
//输入输出程序文件input_output.c
extern int Count; //外部变量声明
void new_student(struct student students[]) //新建学生信息的函数
{
int i,n;
printf("Input n:");
scanf("%d",&n);
printf("Input the student's number,name and course scores\n");
for(i=1;i<=n;i++)
{
printf("No.%d:",i);
scanf("%d%s%d%d%d",&students[i].num,students[i].name,&students[i].math,\
&students[i].english,&students[i].computer);
Count++;
}
}
void output_student(struct student students[]) //输出学生信息的函数
{
int i;
printf("output the student's number,name and course scores\n");
for(i=1;i<=Count;i++)
{
printf("%d\t %s\t %d\t %d\t %d\n",students[i].num,students[i].name,students[i].math,
students[i].english,students[i].computer);
}
}
//计算程序文件computing.c
extern int Count;
void average(struct student students[])
{
int i;
for(i=0;i<Count;i++)
{
students[i].average=(students[i].math+students[i].english+students[i].computer)/3.0;
printf("%.2f\n",students[i].average);
}
}
//修改程序文件update.c
extern int Count;
void modify(struct student *p) //修改学生成绩的函数
{
int i,num,course,score;
printf("Input the number of the students to be updated:");
scanf("%d",&num);
printf("Choice the course:1. math 2. english 3. computer:");
scanf("%d",&course);
printf("Input the new score:");
scanf("%d",&score);
for(i=0;i<Count;i++,p++)
{
if(p->num==num)
{
break;
}
}
if(i<Count)
{
switch(course)
{
case 1:p->math=score;break;
case 2:p->english=score;break;
case 3:p->computer=score;break;
}
}
}
void sort(struct student students[])//平均成绩排序的函数
{
int i,j,index;
struct student temp;
for(i=0;i<Count-1;++i)
{
index=i;
for(j=i+1;j<Count;j++)
{
if(students[j].average>students[index].average)
{
index=j;
}
}
temp=students[index];
students[index]=students[i];
students[i]=temp;
}
}
//查询程序文件search.c
extern int Count;
void search_student(struct student students[],int num)
{
int i,pos;
for(i=0;i<Count;i++)
{
if(students[i].num==num)
{
break;
}
}
if(i<Count)
{
pos=i;
printf("found the %d student\n"num);
}
else
{
pos=-1;
printf("not found the student\n");s
}
}