c程序设计第四版(谭浩强)第八章答案演示教学

1、#include<stdio.h>#include<stdlib.h>#include<string.h>#include<math.h>/*intmain()int*p1,*p2,*p3,*t,a,b,c;printf("enterthreenumber:");scanf("%d%d%d",&a,&b,&c);p1=&a;p2=&b;p3=&c;if(a>b)t=p1;p1=p2;p2=t;if(a>c)t=p1;p1=p3;p3=t;if(b&

2、gt;c)t=p2;p2=p3;p3=t;printf("sortnumber:%d%d%dn",*p1,*p2,*p3);*/*#defineN20intmain()char*p1,*p2,*p3,*t,aN,bN,cN;printf("enterthreestrings:");scanf("%s%s%s",a,b,c);p1=a;p2=b;p3=c;if(strcmp(a,b)>0)t=p1;p1=p2;p2=t;if(strcmp(a,c)>0)t=p1;p1=p3;p3=t;if(strcmp(b,c)>0)

3、t=p2;p2=p3;p3=t;printf("sortstring:%s%s%sn",p1,p2,p3);*/*voidinput(int*p)inti;printf("enter10number:");for(i=0;i<10;i+)scanf("%d",p+i);voidoutput(int*p)inti;printf("new10number:");for(i=0;i<10;i+)printf("%-2d",*(p+i);voidsort(int*p,intn)inti,t;

4、for(i=0;i<n-1;i+)if(*(p+i)>*(p+i+1)t=*(p+i);*(p+i)=*(p+i+1);*(p+i+1)=t;for(i=n-2;i>0;i-)if(*(p+i-1)>*(p+i)t=*(p+i);*(p+i)=*(p+i-1);*(p+i-1)=t;intmain()inta10,*p=a;input(p);sort(p,10);output(p);putchar('n');*/*#defineN10voidhouyi(int*p,intm)inti,bN=0;for(i=0;i<N-m;i+)bi+m=*(p+i

5、);for(;i<N;i+)bi-N+m=*(p+i);for(i=0;i<N;i+)printf("%3d",bi);intmain()intaN,i,m,*p=a;printf("enternumber:");for(i=0;i<N;i+)scanf("%d",&ai);printf("enterm:");scanf("%d",&m);printf("newnumber:");houyi(p,m);putchar('n')

6、;*/*intmain()intcount(int*p,intn);intn,*p,i;printf("enternumber:");scanf("%d",&n);p=(int*)calloc(n,sizeof(int);for(i=0;i<n;i+)*(p+i)=0;printf("thelastnumberis%dn",count(p,n)+1);free(p);intcount(int*p,intn)inti,j=1,k=0;for(i=0;i<n;i+)if(*(p+i)!=3)*(p+i)=j;if(*(

7、p+i)=3)j=1;/数到3时将下一个重置为1elsej+=1;if(i=(n-1)i=-1;/轮到到最后一个人报数时，将i重置为-1,执行完for语句后自动加一变为0，从头开始k+=1;/报完一个数后加一elseif(i=(n-1)i=-1;/检查到最后一个人是3时，将i重置为-1，执行完for语句后自动加一变为0，从头开始continue;/检查到这个人是3时，跳过报数if(k=3*(n-1)/报数的总个数达到3*(n-1)时，就只剩一个人了break;elsecontinue;for(i=0;i<n;i+)if(*(p+i)=3)continue;elsereturni;*/*#

8、defineN20intlength(char*p)intn=0;while(*p!=0)p+;n+=1;returnn;intmain()charaN,*p=a;printf("enterstring:");gets(a);printf("字符串长度为:%dn",length(p);*/*#defineN10intmain()voidcopyn(char*p,intm);char*p="abcdefghij"intm;printf("%snenterm:",p);scanf("%d",&

9、;m);copyn(p,m);voidcopyn(char*p,intm)charbN,i;for(i=m-1;*(p+i);i+)bi-m+1=*(p+i);bi-m+1='0'printf("%sn",b);*/*#defineN50voidcount(char*p)intd=0,x=0,k=0,s=0,o=0;while(*p)/不能写*(p+),否则计算出错,无法计算第一个字符if(*p>='a'&&*p<='z')x+=1;elseif(*p>='A'&&am

10、p;*p<='Z')d+=1;elseif(*p>='0'&&*p<='9')s+=1;elseif(*p='')k+=1;elseo+=1;p+;printf("大写字母:%dn小写字母:%dn空格:%dn数字:%dn其他:%dn",d,x,k,s,o);intmain()charaN,*p=a;printf("enterstring:");gets(a);count(p);*/*voidzhuangzhi(int(*p)3)inti,j,t;for(i=

11、0;i<3;i+)forO=0;j<3;j+)if(i<j)(t=*(*(P+i)+j)；*(*(P+i)+j)代表aij*(*(P+i)+j)=*(*(P+j)+i)；*(*(p+j)+i)寸)intmain()(int(*p)3,a33,ij;P=a;printf("enterarray:n");for(i=0;i<3;i+)forO=0;j<3;j+)scanf("%d",&aij);zhuangzhi(p);printf("newarray:n");for(i=0;i<3;i+)fo

12、rO=0;j<3;j+)(printf("%-2d",aij);if(j=2)putchar('n');)*/*voidcentral(int(*p)5)(intij,l=O,r=O,t;代表行，I代表列for(i=0;i<5;i+)for(j=0;j<5;j+)if(*(*(P+i)+j)>*(*(P+r)+l)(r=i；l=j；)t=*(*(p+2)+2);*(*(p+2)+2)=*(*(p+r)+l);*(*(p+r)+l)=t;/最大元素放在中心l=0;r=0;for(i=0;i<5;i+)/四个角放最小元素，每次从第二

13、个元素开始对比for(j=1；j<5;j+)if(*(*(P+i)+j)<*(*(P+r)+l)r=i；l=j；/找出最小元素)t=*(*p)；*(*p)=*(*(p+ij+l)；*(*(p+r)+l)=t;同l=4;r=0;for(i=0;i<5;i+)for(j=1；j<5;j+)if(*(*(P+r)+l)>*(*(P+i)+D)(r=i；l=j；)t=*(*p+4)；*(*p+4)=*(*(p+ij+l);*(*(p+ij+l)=t；r=4;l=0;for(i=0;i<5;i+)for(j=1；j<5;j+)if(i=0&&j=

14、4)continue;elseif(*(*(p+ij+l)>*(*(p+i)+j)(r=i；l=j；)t=*(*(p+4)；*(*(p+4)=*(*(p+r)+|)；*(*(p+r)+l)=t;r=4;l=4;for(i=0;i<5;i+)for(j=1；j<5;j+)if(i=O&&j=4|i=4&&j=O)continue;elseif(*(*(p+r)+l)>*(*(p+i)+j)(r=i；l=j；将最小元素与左上角元素交换，下/换完重置r和I,下同遇到右上角，跳过对比遇到右上角和左下角，跳过对比)t=*(*(p+4)+4);*(*

15、(p+4)+4)=*(*(p+r)+l);*(*(p+ij+l)=t;)intmain()(inta55,(*p)5=a,ij;printf("enterarray:n");for(i=0;i<5;i+)for(j=0;j<5;j+)scanf("%d",*(p+i)+j);central(p);printf("newarray:n");for(i=0;i<5;i+)for(j=0;j<5;j+)printf("%-3d",*(*(p+i)+j);putchar('n');*

16、/*voidsort(char*p,intn)/指针数组处理inti,j;char*k;for(i=1;i<n;i+)for(j=i;j<n;j+)if(strcmp(pi-1,pj)>0)k=pi-1;pi-1=pj;pj=k;intmain()char*p10="gutsy","glory","gonad","girth","gaudy","gypsy","gusto","guppy","group&qu

17、ot;,"grope"/测试数据gutsyglorygonadgirthgaudygypsygustoguppygroupgropeinti;printf("enterstrings:");for(i=0;i<10;i+)printf("%s",pi);sort(p,10);printf("nnewstrings:");for(i=0;i<10;i+)printf("%s",pi);putchar('n');*/*#defineN20voidsort(char*p,i

18、ntn)/指针处理inti,j;charkN;for(i=1;i<n;i+)for(j=i;j<n;j+)if(strcmp(p+20*(i-1),p+20*j)>0)/不能写为p+i-1，否则出错strcpy(k,p+20*(i-1);strcpy(p+20*(i-1),p+20*j);strcpy(p+20*j,k);intmain()chara10N;char*p=a0;/不能写为*p=a，这等价于是把行向量赋值给列向量inti;printf("enterstrings:n");for(i=0;i<10;i+)scanf("%s&qu

19、ot;,&ai);可写为gets(ai),这样写的话，每次输入字符串后按enter,或写为scanf("%s",&ai)，每输一个字符后按空格即可;sort(p,10);printf("newstrings:n");for(i=0;i<10;i+)printf("%s",ai);putchar('n');*/*#definen1000/矩形法求定积分,n为区间分割数目doubleding(doublea,doubleb,double(*fun)(double)doubles=0;inti;for(

20、i=1;i<n;i+)s+=(*fun)(i*(b-a)/n);returns*=(b-a)/n;intmain()doublea,b,s1,s2,s3;/定义积分下限，上限,用double精度较高printf("输入积分下限，上限，分割区间数目:");scanf("%lf%lf",&a,&b);s1=ding(a,b,sin);s2=ding(a,b,cos);s3=ding(a,b,exp);printf("sin(x)从£到£的积分为%fn",a,b,s1);printf("c

21、os(x)从£到£的积分为fn",a,b,s2);printf("exp(x)从£至1%£的积分为fn",a,b,s3);*/*#defineN10voidnixu(int*p)inti,m=N/2,t;for(i=0;i<m;i+)t=*(p+i);*(p+i)=*(p+N-1-i);*(p+N-1-i)=t;intmain()intaN,*p=a,i;printf("enter%dnumbers:n",N);for(i=0;i<N;i+)scanf("%d",&

22、ai);nixu(p);printf("newnumbers:n");for(i=0;i<N;i+)printf("%d",ai);putchar('n');*/*voidaverage1(float(*p)6,intn)inti;floatave=0;for(i=0;i<n;i+)ave+=*(*(p+i)+1)/4;printf("第一门课程的平均分为：%4.2fn",ave);floataverage(float(*p)6)inti;floatave=0;for(i=1;i<6;i+)ave+=

23、*(*p+i)/5;returnave;voidout(float(*p)6,intn)inti,j,k,l,s=0;printf("两门课以上不及格的学生：n");for(i=0;i<n;i+)k=0;for(j=1;j<6;j+)if(*(*(p+i)+j)<60)k+=1;elsecontinue;if(k>=2)s=1;printf("%4.0f",*(*(p+i);for(l=1;l<6;l+)printf("%4.0f",*(*(p+i)+l);printf("平均分为:%4.2fn

24、",average(p+i);if(s=0)/没有符合条件的学生时输出“无”printf("无!n");voidin(float(*p)6,intn)inti,j,l;for(i=0;i<n;i+)for(j=0;j<6;j+)if(average(p+i)>=90)printf("平均分在90分以上的学生:%4.0f",*(*(p+i);for(l=1;l<6;l+)printf("%4.0f",*(*(p+i)+l);putchar('n');break;if(*(*(p+i)+j

25、)>=85)continue;elsebreak;if(j=6)printf("全部课程成绩在85分以上的学生:%4.0f",*(*(p+i);for(l=1;l<6;l+)printf("%4.0f",*(*(p+i)+l);putchar('n');intmain()inti,j;floata46=1001,65,67,55,60,45,1002,80,87,90,81,85,1003,90,99,100,98,95,1004,86,89,90,91,85;float(*p)6=a;for(i=0;i<4;i+)fo

26、r(j=0;j<6;j+)printf("%4.0f",aij);putchar('n');average1(p,4);out(p,4);in(p,4);*/*/ 方法一/ 将数字字符串转为整形数字的函数/j 用于计算数字长度， k 用于计算数字个数/ 最多容纳 N 个整数#defineN10intnum1(char*p)intn=strlen(p),i,a=0;for(i=0;i<n;i+)a+=(int)(*(p+i)-48)*pow(10,n-1-i);returna;voidnumber(char*p)inti,num=0,j=1,k=-

27、1,n=strlen(p);intaN;for(i=0;i<=n;i+)if(*p<'0'|*p>'9')if(num=1)*p='0'ak=num1(p-j);num=0;elseif(num=0)num=1;j=1;/找到新数字时重置jk+=1;elsej+=1;p+;for(i=0;i<k+1;i+)printf("%d",ai);putchar('n');*/*#defineN10voidnumber(char*p)/方法二inti,num=0,j=1,k=-1,n=strlen

28、(p);/j用于计算数字长度，k用于计算数字个数charaN10;/最多容纳N个整数，每个整数最多十位数for(i=0;i<=n;i+)if(*p<'0'|*p>'9')if(num=1)*p='0'strcpy(ak,p-j);num=0;elseif(num=0)num=1;j=1;/找到新数字时重置jk+=1;elsej+=1;p+;for(i=0;i<k+1;i+)printf("%s",ai);putchar('n');intmain()chara100,*p=a;/最多可输入

29、100个字符printf("enterstrings:n");gets(p);number(p);*/*#defineN20/字符串比较函数intstr_cmp(char*p1,char*p2)inti,n=strlen(p1);for(i=0;i<=n;i+)if(*(p1+i)=*(p2+i)continue;elseif(*(p1+i)>*(p2+i)return*(p1+i)-*(p2+i);break;elsereturn*(p1+i)-*(p2+i);break;if(i=n+1)return0;intmain()charaN,bN,*p1=a,*p

30、2=b;printf("enterstring1:");gets(p1);printf("enterstring2:");gets(p2);printf("%dn",str_cmp(p1,p2);*/*voidmonth(int*p)char*a12="January","February","March","April","May","June","July","August"

31、;,"September","October","Novenber","December"inti;for(i=0;i<12;i+)if(*p=i+1)printf("英文:%sn",ai);elsecontinue;intmain()inta,*p=&a;printf("entermonth:");scanf("%d",p);month(p);*/*#defineSIZE1000charnewbufSIZE;char*newp=newbuf;char*mynew(intn)回指针if(newp+n<=newbuf+SIZE)newp+=n;return(newp-n);elsereturn(NULL);voidfree(char*p)if(p>=newbuf&&p<newbuf+SIZE)newp=p;/定义字符数组newbuf/定义指针变量newp，指向可存区的始端/定义开辟存区的函数new,开辟存储区后