C语言程序设计教程杨路明课后习题答案.docx

1、C语言程序设计教程杨路明课后习题答案C语言程序设计教程 杨路明 课后习题答案 北京邮电大学出版社第一章1、算法描述主要是用两种基本方法：第一是自然语言描述，第二是使用专用工具进行算法描述2、c语言程序的结构如下：c语言程序由函数组成，每个程序必须具有一个main函数作为程序的主控函数。/*与*/之间的内容构成c语言程序的注释部分。用预处理命令#include可以包含有关文件的信息。大小写字母在c语言中是有区别的。除main函数和标准库函数以外，用户可以自己编写函数，程序一般由多个函数组成，这些函数制定实际所需要做的工作。例如：void main()int a,b,c,s;a=8;b=12;c=

2、6;s=a b*c;printf(s=%d,s);3、c语言的特点：c语言具有结构语言的特点，程序之间很容易实现段的共享；c语言的主要结构成分为函数，函数可以在程序中被定义完成独立的任务，独立地编译成代码，以实现程序的模块化。c语言运算符丰富，运算包含的范围很广；c语言数据类型丰富。c语言允许直接访问物理地址，即可直接对硬件进行操作，实现汇编语言的大部分功能；c语言语法限制不太严格，程序设计自由度大，这样是c语言能够减少对程序员的束缚；用c语言编程，生成的目标代码质量高，程序执行效率高，可移植性好；4、合法标识符：AB12、leed_3、EF3_3、_762、PAS、XYZ43K2不合法标识符

3、：a*b2、8stu、D.K.Jon、if、ave#xy、#_DT5、C.D5、F2:将当前编辑器中文件存盘F10:调用主菜单F4:程序运行到光标所在行Ctrl F9:当前编辑环境下，进行编译、连接且运行程序；Alt F5:将窗口切换到DOS下，查看程序运行结果6、(1):*welcome youvery good*(2):please input three number;5,7,8max number is:87、main8、User screen、Alt F59、标识符必须是字母或下划线开头，大小写字母含义不同。由数字、字母和下划线组成；关键字是一种语言中规定具有特定含义的标识符。关键字

4、不能作为变量或函数名来使用，用户只能根据系统的规定使用它们。10、选择主菜单File项下拉子菜单中Save项或直接按F2键存盘。第二章1、符合C语法规定的常数为：0x1e、ab、1.e52、(1):错误如下：int x,y=5,z=5,aver;x=7;aver = (x y x)/3;结果如下：AVER=5(2):错误如下：char c1=a,c2=b,c3=c;printf(a=?=_end,a,b);结果如下：a=3b=Aendaabcc abc3、4、(1):9,11,9,10(2):3,1,0,0(3):11,19,31,15、(1):0(2):0(3):9.500000(4):90

5、(5):10(6):10(7):65(8):4(9):4.500000(10):1(11):0(12):20(13):06、(5)7、求x的绝对值8、c(max=ab?a:b)?c:max;9、B10、D第三章1、输入函数scanf的参数错误，应该为：scanf(%f,&k);2、|1234 1234 |3、ff104、1,3,15、原字符串左边加空格再加字符串本省，字符个数总和为5个6、scanf(%d,%d,%c,%c,&a1,&a2,&c1,&c2);7、printf(a b=%d,a b);printf(a-b=%d,a-b);printf(a*b=%d,a*b);printf(a/b

6、=%d,a/b);printf(float)a/b=%f,(float)a/b);printf(a%b=%d,a%b);8、void main()float r;float s,c;printf(please input the number:);scanf(%f,&r);if(r=0)s = 3.14*r*r;c = 2*3.14*r;printf(s = %f, c = %f,s,c);elseprintf(you input number is error!);9、void main()int n;printf(please input the number:);scanf(%d,&n)

7、;if(n=100 & n printf(%d%d%d,n_,(n/10)_,n/100);elseprintf(you input number is error!);10、void main()int i,j,k;scanf(%d,%d,%d,&i,&j,&k);(i%2 != 0?1:0) (j%2 != 0?1:0) (k%2 != 0?1:0) = 2?printf(YES):printf(NO);11、void main()char a;scanf(%c,&a);printf(%c,%c,%c,a-1,a,a 1);printf(%d,%d,%d,a-1,a,a 1);12、voi

8、d main()float a,b,c,s,Area;scanf(%f,%f,%f,&a,&b,&c);if(a b c | a c b | b c a)s = (a b c)/2;Area = sqrt(s*(s-a)*(s-b)*(s-c);printf(%f,Area);elseprintf(you input the number is error!);第四章1： 02： 203： (x20)|(x4: *a=25,b=14,c=16*5: 376: if(aelse printf(2);7、#includevoid main()char a,b,t1,t2;scanf(%c,%c,&

9、a,&b);t1=ab?a:b;t2=aif(t1-t2)%2=0)printf(%c,%c,a 1,b 1);else printf(%c,%c,a-1,b-1);getch();8、#includevoid main()int temp1=0,temp2=0,x,y,i=1;printf(Please input (x,y): );scanf(%d,%d,&x,&y);while(i*y)if(x=(i*y) temp1=1;break;temp2=i;i ;if(temp1)printf(%d / %d = %d,x,y,i);elseprintf(%d / %d- shang=%d,y

10、ushu=%d,x,y,temp2,x-y*temp2);getch();9、#includevoid main()float x,y,m=0,n=0;scanf(%f,%f,&x,&y);n=(x-2)*(x-2);m=(y-2)*(y-2);if(m n)printf(%.3f,%.3f)In the yuan,x,y);elseprintf(%.3f,%.3f)out of the yuan,x,y);getch();10、#includevoid main()int temp=0,month,year;printf(Please input (year,month): );scanf(

11、%d,%d,&year,&month);if(year0=0)|(year%4=0&year_0!=0)temp=1;if(month=2)if(temp)printf(%d year %d month have 29 ,year,month);else printf(%d year %d month have 28 ,year,month);else if(month%2=0)printf(%d year %d month have 30 ,year,month);else printf(%d year %d month have 31 ,year,month);getch();11、swi

12、tch(a/10)case 5:m=4;break;case 4:m=3;break;case 3:m=2;break;case 2:m=1;break;default:m=5;12、方法一：#includevoid main()int x,y;scanf(%d,&x);if(x-5)y=x-1;else if(x=0)y=x;else if(x0&xy=x 1;printf(%d,y);getch();方法二：#includevoid main() int x,y;scanf(%d,&x);if(x-5) if(x=0)y=x;else if(x0&xelse y=x-1;printf(%d

13、,y);else printf(Input error!);getch();方法三：#includevoid main() int x,y,i;scanf(%d,&x);if(x-5) if(x=0)i=1;else if(x0&xelse i=3;else i=4;switch(i) case 1:y=x;printf(%d,y);break;case 2:y=x 1;printf(%d,y);break;case 3:y=x-1;printf(%d,y);break;case 4:printf(Input error!);break;getch();第五章1、void main()int

14、n,value;int i,count=0;float average = 0;long int sum = 0;scanf(%d,&n);for(i = 0; i scanf(%d,&value);if(value%2 = 0)sum =value;count ;average = sum / (float)count;printf(the average is %f,average);2、#include stdio.hvoid main()char ch;int zm = 0, sz = 0;ch = getchar();while(ch != *)if(ch = A & ch = a

15、& ch zm ;if(ch = 0 & ch sz ;ch = getchar();printf(zm = %d ; sz = %d,zm,sz);3、void main()long i_value;int sum = 0;int temp = 0;scanf(%ld,&i_value);if(i_value for(;)temp = i_value_;i_value = i_value/10;sum =temp;printf(%d ,temp);if(i_value = 0)break;printf(=%d,sum);4、#include stdio.hvoid main()char ch

16、;ch = getchar();while(ch != .)if(ch = A & ch ch = ch 32;putchar(ch);else if(ch = a & ch ch = ch - 32;putchar(ch);elseputchar(ch);ch = getchar();printf();5、void main()float sum = 200;int count = 0;for(;)sum = sum sum*0.045;count ;if(sum 500)break;printf(the %d years later complete!,count);6、void main

17、()int i,temp=0,bit=0;for(i = 1 ; i if(i%3 = 0)temp = i;for(;temp != 0;)bit = temp_;if(bit = 5)printf(%d,i);break;temp = temp/10;printf();7、#include int main(void)int steps = 29, i = 1;while ( steps % 7 )steps = (30 * i) - 1;printf(Total steps: %d, steps);return 0;8、main()int i,j,k,n;printf(the narci

18、ssus number is:);for(n=100;ni=n/100;j=n/10-i*10;k=n_;if(i*i*i j*j*j k*k*k=n) printf(%d,n);9、main() float i,j,temp,n,sum;int t;i=2;j=1;sum=0;scanf(%d,&t);for(n=1;nsum=sum i/j;temp=i;i=i j;j=temp;printf(2/1 3/2 5/3 8/5 13/8 .=%f,sum);10、void main()int nWidth,a,b;scanf(%d,&nWidth);for(a=(nWidth%2);afor

19、(b=0;bchar chOut = ;int nleft =(nWidth -a)/2;int nright = (nWidth a)/2;if(b=nleft&bchOut =*;printf(%c,chOut);printf();r11、void main()int i=1,j=1;for(i=1;ifor(j=1;jprintf(%d*%d=%d,i,j,i*j);printf()12、#include stdio.hvoid main()char c;/count1是正数的个数/count2是负数的个数int count1=0,count2=0;/sum1是正数之和/sum2是负数之

20、和int sum1=0,sum2=0;int flage = 0;c=getchar();while(c != *)if(c = -)flage = 1;if(flage = 0)sum1 =(c-48);count1 ;elseif(c != -)sum2-=(c-48);flage=0;count2 ;c = getchar();printf(%d,%d,count1,count2);printf(%f,%f,sum1/count1,sum2/count2);13、void main()int i,j;int s = 0;for(i = 100 ; i s = 0;for(j=1; j i

21、f( i%j = 0 ) s = s j;if(s = i)printf(,i);14、#include #include void main()int n;long k = 1;float e = 1;n = 1;clrscr();while ( fabs(1.0/k) = 0.000001)n ;e = e 1.0/k;k = k * n;printf(%f,e);15、#include math.hmain()float x0,x1,x2,f0,f1,f2;x1=-10;f1=2*x1*x1*x1-4*x1*x1 3*x1;x2=10;f2=2*x2*x2*x2-4*x2*x2 3*x2

22、;do x0=(x1 x2)/2;f0=2*x0*x0*x0-4*x0*x0 3*x0;if(f0*f1)x2=x0; f2=f0;elsex1=x0; f1=f0;while(fabs(f0)1e-6);printf(_2*x*x*x-4*x*x 3*x=0_:n);printf(the root is %f,x0);第六章1、#includeint divisor(int a,int b) int r;while(r=a%b)!=0) a=b;b=r;return b;int multiple(int a,int b) int d;d=divisor(a,b);return a*b/d;v

23、oid main() int a,b,c,d;printf(intput (a,b): );scanf(%d,%d,&a,&b);c=divisor(a,b);d=multiple(a,b);printf(=%d=%d,c,d);2、#includevoid tongji(char a) int b3=0,0,0,i=0;while(ai!=) if(ai=65)|(ai=97)b0 ;else if(ai=48)b1 ;elseb2 ;i ;printf(zimu have: %d; shuzi have: %d; qita have: %d,b0,b1,b2);getch();void m

24、ain() char a100;printf(Please input a string: );gets(a);tongji(a);3、#includeint flower(int n) int x=0,i,j,k;i=(n_);j= (n/10_);k=(n/100);x=i*i*i j*j*j k*k*k;if(x=n) return 1;else return 0;void main() int i,n;printf(Please intput n: );scanf(%d,&n);if(n999|nelse for(i=100;iif(flower(i)printf(%d ,i);get

25、ch();4、#include#define S) t=b;b=a;a=t;main() float x,y,t;printf(Enter two number (x,y): );scanf(%f,%f,&x,&y);S);printf(:x=%f,y=%f,x,y);getch();5、#includeint fib(int n) int p;if(n=0) p=0;else if(n=1) p=1;else p=fib(n-1) fib(n-2);return p;void main() int n;printf(Please input fib: );scanf(%d,&n);print

26、f(=%d,fib(n);6、#includelong fac(int n) long f;if(n=0) f=1;else f=n*fac(n-1);return f;void main() int m,n;long f;printf(Please input (m,n): );scanf(%ld,%ld,&m,&n);f=fac(n m) fac(n);printf(=%ld,f);7、#includevoid list() int i,j;for(i=1;i for(j=1;jprintf(%d*%d=%d ,i,j,i*j);printf();void main() list();8、

27、#includeint he(int n) int i,s=0;for(i=1;iif(n%i=0)s =i;return s;void main() int i,j;for(i=1;ifor(j=1;jif(he(i)=j)&(he(j)=i)&(i!=j)printf(%d%d ,i,j);9、#include#define max 100struct work long sid;char name15;workermax;int size=0;struct work *set_list() do printf(input (sid,name): );scanf(%ld,%s,&workersize.sid,workersize.name);size ;while(workersize-1.sid!=0);return worker;void paixu(struct work a) int i,j,k;long t;char v15;for(i=0;i k=i;for(j=i;jif(ai.sidaj.sid)k=j;if(k!=i) t=ai.sid; ai.sid=aj.sid; aj.sid=t;strcpy(v,ai.name);strcpy(ai.name,aj.name);strcpy(aj.name,v); f