第八章作业参考答案

第八章练习题P.1968_1（1）地址变量不能输入；（2）p2没有初始化，即悬空时不能对其所指的内存赋值；（3）~（5）同类型的指针之间才能相互赋值。

8_2#include<iostream.h>void swap(float *p1,float *p2){ float p;p=*p1;*p1=*p2;*p2=p;}void main(){ float a,b,c;cin>>a>>b>>c;if(a>b)swap(&a,&b);if(b>c)swap(&b,&c);if(a>b)swap(&a,&b);cout<<a<<'\t'<<b<<'\t'<<c<<endl;}8_3#include<iostream.h>#include<string.h>#define N 10 //二维数组的行数#define M 80 //二维数组的列数void sort(char s[][M],int n){ int i,j,k;char s1[80];for(i=0;i<n-1;i++){k=i;for(j=i+1;j<n;j++)if(strcmp(s[k],s[j])>0)k=j;if(k!=i){ s trcpy(s1,s[k]);strcpy(s[k],s[i]);strcpy(s[i],s1);} }}void main(){ int i,n;char str[N][M];cout<<"请输入字符串的个数（小于等于10）！"<<'\n'<<"字符串的个数是：";cin>>n; //二维数组的实际行数cout<<"请输入字符串（以回车符结束每个字符串的输入）！"<<'\n';for(i=0;i<=n;i++)cin.getline(str[i],80);sort(str,n);cout<<'\n'<<"排序后的字符串为：";for(i=0;i<=n;i++)cout<<str[i]<<endl;8_4#include<iostream.h>#define N 100 //最大可处理的实数个数float *insert(float *p,float value){ float *p0,*p1;p0=p; //保存数组的首指针while(value>=*p&&*p!=0)p++;p1=p; //要插入的位置while(*p!=0)p++;//与下一行共同使要插入位置以后的元素下移while(p!=p1){*p=*(p-1);p--;}*p=value; //插入return p0; //返回首指针}void main(){ int i,n;cout<<"请输入要处理的实数的个数！"<<'\n'<<"实数的个数是：";cin>>n;cout<<'\n';float f,a[N],*p;p=a;for(i=0;i<n;i++)a[i]=0;//初始化数组for(i=0;i<n;i++){cout<<"请输入元素的值:";cin>>f; p=insert(p,f);}cout<<'\n'<<"排好序的数据为：";for(i=0;i<n;i++)cout<<*p++<<'\t';cout<<endl;}8_5#include<iostream.h>int strlen(char *ptr){ int i=0;while(*ptr++)i++;return i;}void main(){ int n;char s[201];cin.getline(s,200);cout<<"s="<<s<<'\n';n=strlen(s);cout<<"strlen(s)="<<n<<endl;}#include<iostream.h>char *strcat(char *ptr1,char *ptr2){ char *ptr=ptr1;while(*ptr1++);ptr1--;while(*ptr2)*ptr1++=*ptr2++;*ptr1='\0';return ptr;}void main(){ char s1[41],s2[41],*s;cin.getline(s1,40);cin.getline(s2,40);cout<<"s1="<<s1<<'\n'<<"s2="<<s2<<endl;s=strcat(s1,s2);cout<<"s1+s2="<<s<<endl;}8_7#include<iostream.h>char *strcpy(char *ptr1,char *ptr2,int n){ int i=0;char *ptr=ptr1,*ptr0;while(*ptr1++);ptr1--;ptr0=ptr1;ptr1=ptr;while(i++<n)ptr1++;ptr1--;while(*ptr2)*ptr1++=*ptr2++;if(ptr1>ptr0)*ptr1='\0';return ptr;}void main(){ int n;char s1[41],s2[41],*s;cin.getline(s1,40);cin.getline(s2,40);cout<<"s1="<<s1<<'\n'<<"s2="<<s2<<endl;cin>>n;s=strcpy(s1,s2,n);cout<<"(s1,s2,"<<n<<")="<<s<<endl;}8_8#include<iostream.h>void fun(float (*p)[6],int n,float*max,float*min,float&ave) { *min=*max=(*p)[0];ave=0;for(int i=0;i<n;i++)for(int j=0;j<6;j++){ave+=*(*(p+i)+j);if(*(*(p+i)+j)>*max)*max=*(*(p+i)+j);if(*(*(p+i)+j)<*min)*min=*(*(p+i)+j);}ave/=6*n;}void main(){ float a[6][6];float ma,mi,av;for(int i=0;i<6;i++)for(int j=0;j<6;j++)a[i][j]=(float)i*6+j;fun(a,6,&ma,&mi,av);cout<<"max="<<ma<<'\n'<<"min="<<mi<<'\n'<<"average="<<av<<endl; }8_9#include<iostream.h>#include<math.h>double f1(double x){return 1/(2+sin(x));}double f2(double x){return 1/(2-cos(x));}double f3(double x){return (1+x)/(1+x*x);}double fun(double(*fp)(double),double a1,double a2,int n){ double h=(a2-a1)/n,x=a1,s=0;for(int i=1;i<=n;i++){x+=h;s+=fp(x)*h;}return s;}void main(){ cout<<"积分区间等分数为1000时：\n";cout<<"f1="<<fun(f1,1,2,1000)<<'\t';cout<<"f2="<<fun(f2,2,3,1000)<<'\t';cout<<"f3="<<fun(f3,2,4,1000)<<'\n';cout<<"积分区间等分数为2000时：\n";cout<<"f1="<<fun(f1,1,2,2000)<<'\t';cout<<"f2="<<fun(f2,2,3,2000)<<'\t';cout<<"f3="<<fun(f3,2,4,2000)<<'\n';cout<<"积分区间等分数为3000时：\n";cout<<"f1="<<fun(f1,1,2,3000)<<'\t';cout<<"f2="<<fun(f2,2,3,3000)<<'\t';cout<<"f3="<<fun(f3,2,4,3000)<<'\n';}8_10#include<iostream.h>#include<string.h>void input(char *p1[10]){ char s[51];for(int i=0;i<10;i++){cin.getline(s,50);p1[i]=new char[strlen(s)+1];strcpy(p1[i],s);}}void sort(char*p2[10]){for(int i=0;i<9;i++)for(int j=i+1;j<10;j++)if(strcmp(p2[i],p2[j])>0){char*t=p2[i];p2[i]=p2[j];p2[j]=t;}}void main(){ char *p[10];cout<<"请输入10个字符串：\n";input(p);sort(p);cout<<"排序后的字符串是：\n";for(int i=0;i<10;i++){cout<<p[i]<<endl;delete[strlen(p[i]+1)]p[i];}}8_11#include<iostream.h>int num(char *s,int t[]){ int i=0;for(t[i]=0;*s;s++){if((*s>='0')&&(*s<='9')){t[i]=t[i]*10+(*s-'0');if((*(s+1)<'0')||(*(s+1)>'9')){i++;t[i]=0;}}}return i;}void main(){ char str[81];cout<<"请输入一个字符串：\n";cin.getline(str,79);int b[20],n;n=num(str,b);cout<<"字符串是：\n"<<str<<'\n';cout<<"其中的整数分别是：\n";for(int i=0;i<n;i++)cout<<b[i]<<'\t';cout<<endl;}8_12#include<iostream.h>#define NULL 0struct NODE{int id,age;char name[10];float c;NODE *next;};NODE *Create(int n){ NODE *p1,*p2,*h=0;int i=0;while(i<n){p1=new NODE;cin>>p1->id>>p1->name>>p1->age>>p1->c;if(h==0){h=p1;p2=p1;}else{p2->next=p1;p2=p1;}i++;}p2->next=0;return h;}void print(NODE *h){ NODE *p;p=h;while(p!=0){ cout<<p->id<<'\t'<<p->name<<'\t'<<p->age<<'\t'<<p->c<<endl;p=p->next;}cout<<endl;}void deletechain(NODE *h){ NODE *p;while(h){ p=h;h=h->next;delete p;}}void main(){ int n;cout<<"请输入班级人数！"<<endl<<"班级人数为：";cin>>n;cout<<endl;cout<<"请输入班级学生信息！"<<endl;cout<<"学号姓名年龄C++成绩"<<endl;NODE *h;h=Create(n);cout<<endl<<"学号姓名年龄C++成绩"<<endl;print(h);deletechain(h);}8_13#include<iostream.h>#define NULL 0struct NODE{int id,age;char name[10];float c;NODE *next;};NODE *Create(int n){ NODE *p,*p1,*p2,*h=NULL;int i=0;if(n<1)return NULL;while(i<n){p=new NODE;cin>>p->id>>p->name>>p->age>>p->c;p->next=NULL;if(h==NULL)h=p;else{p1=p2=h;while(p2&&p->c>=p2->c){ p1=p2;p2=p1->next;}if(p2==h){p->next=p2;h=p;}else{p->next=p2;p1->next=p; }}i++;}return h;}void print(NODE *h){ NODE *p;p=h;while(p!=0){cout<<p->id<<'\t'<<p->name<<'\t'<<p->age<<'\t'<<p->c<<endl;p=p->next;}cout<<endl;}void deletechain(NODE *h){ NODE *p;while(h){ p=h;h=h->next;delete p;}}void main(){ int n;cout<<"请输入班级人数！"<<endl<<"班级人数为：";cin>>n;cout<<endl;cout<<"请输入班级学生信息！"<<endl;cout<<"学号姓名年龄C++成绩"<<endl;NODE *h;h=Create(n);cout<<endl<<"学号姓名年龄C++成绩"<<endl;print(h);deletechain(h);}8_14#include<iostream.h>#define NULL 0struct NODE{int id,age;char name[10];float c,maths,english;NODE *next;};NODE *Create(int n){ NODE *p1,*p2,*h=0;int i=0;while(i<n){p1=new NODE;cin>>p1->id>>p1->name>>p1->age>>p1->c>>p1->maths>>p1->english;if(h==0){h=p1;p2=p1;}else{p2->next=p1;p2=p1;}i++;}p2->next=0;return h;}void print(NODE *h){ NODE *p;p=h;NODE *max,*min;max=min=h;float sum=0;while(p!=0){sum=(p->c+p->maths+p->english);if(sum>(max->c+max->maths+max->english))max=p;if(sum<(min->c+min->maths+min->english))min=p;p=p->next;}cout<<"最高分："<<max->id<<'\t'<<max->name<<'\t'<<max->age<<'\t'<<max->c<<'\t'<<max->maths<<'\t'<<max->english<<endl;cout<<"最低分："<<min->id<<'\t'<<min->name<<'\t'<<min->age<<'\t'<<min->c<<'\t'<<min->maths<<'\t'<<min->english<<endl;cout<<endl;}void deletechain(NODE *h){ NODE *p;while(h){ p=h;h=h->next;delete p;}}void main(){ int n;cout<<"请输入班级人数！"<<endl<<"班级人数为：";cin>>n;cout<<endl;cout<<"请输入班级学生信息！"<<endl;cout<<"学号姓名年龄C++成绩maths english"<<endl;NODE *h;h=Create(n);cout<<endl<<" 学号姓名年龄C++ maths english"<<endl;print(h);deletechain(h);}8_15#include<iostream.h>#define NULL 0struct NODE{int data;NODE *next;};NODE *Create(int n){ NODE *p1,*p2,*h=NULL;int i=0;while(i<n){p1=new NODE;cin>>p1->data;if(h==NULL){h=p1;p2=p1;}else{p2->next=p1;p2=p1;}i++;}p2->next=NULL;return h;}NODE *Reverse(NODE *h_head){ NODE *p1=NULL,*p2=h_head,*temp,*h_end=h_head;while(h_end->next)h_end=h_end->next;//定位于链尾while(p2!=h_end){temp=p2->next;p2->next=p1;p1=p2;p2=temp;}p2->next=p1;return h_end;}void print(NODE *h){ NODE *p;p=h;while(p!=0){cout<<p->data<<'\t';p=p->next;}cout<<endl;}void deletechain(NODE *h){ NODE *p;while(h){ p=h;h=h->next;delete p;}}void main(){ int n;cout<<"请输入结点数！"<<endl<<"结点数为：";cin>>n;cout<<endl;cout<<"请输入结点中的data值！"<<endl;NODE *h,*h1;h=Create(n);print(h);h1=Reverse(h);print(h1);deletechain(h);}。