C语言程序设计（第三版）习题答案.doc

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1、习题解答2第1章2第2章2第3章3第4章4第5章5第6章6第7章8第8章9第9章10第10章11第11章13第12章16习题解答第1章1.C语言程序主要由预处理命令、函数、注释等组成。2.填空(1)分号(2)main(3)stdio.h3.源程序：#includemain( )printf(“*n”);printf(“Hello World!n”);printf(“*”);4.源程序：#include main( )int a, b, c; /* 定义变量 */scanf(“%d”, &a); /* 输入第一个整数 */scanf(“%d”, &b); /* 输入第二个整数 */c=a-b;

2、/* 计算差 */printf(“%d-%d=%d”,a,b,c); /* 输出结果 */5.#include (stdio.h) /* 改为 */main( )int x , y , s ;x=10 /* 改为x=10; */y=20;s=x y ;printf(s = %dn , s ); /* 改为 printf(“s=%dn”,s); */第2章1.(1) c (2) a (3) b (4)b (5) a (6) d (7)c2. a. 5 b. 294 c. 4 d. 29 e. 93. a.x=4,y=6b. x=4,y=3c.x=4,y=4d.x=4,y=8e.x=4,y=9f.

3、x=3,y=64. 165. #includemain()int a,b,c;scanf(%d%d,&a,&b);c=a*b;printf(%d*%d=%d,a,b,c);第3章1.(1) b (2) b (3) d (4) a (5) b (6)a 2. 1233. 9 4.&a,&bl,s5.%.2f %.2f6.#includemain() int num1,num2,num3,sum;float average;scanf(%d%d%d,&num1,&num2,&num3);sum=num1+num2+num3;average=sum/3.0;printf(sum=%d,average

4、=%.2fn,sum,average);5.#includemain() int hour,minute,second,total; /* 定义变量代表时、分、秒和总秒数 */scanf(%d,&total);hour=total/3600;minute=total%3600/60;second=total%3600%60;printf(%dhours:%dminutes:%dsecondsn,hour,minute,second);第4章1.(1) b (2) b (3) b (4) b (5) b2. 03.(1) 6 (2) 4 (3) 1 (4) 1 (5)34. #include m

5、ain( )int x,y;scanf(%d,&x);if (x-5 & x0 & x10)y=2*x+1;printf(x=%d,y=%dn,x,y);5.#include main( )int score,rank; /* score表示成绩,rank表示级别 */printf(Please input score:);scanf(%d,&score);rank=score/10;switch(rank)case 10: case 9: printf(成绩等级为：An); break; case 8: printf(成绩等级为：Bn); break; case 7: printf(成绩等级

6、为：Cn); break; case 6: printf(成绩等级为：Dn); break; default:printf(成绩等级为：En); break;6.#includevoid main()int n;printf(Please input the digit:);scanf(%d,&n);switch(n)case 1:printf(Jan n);break;case 2:printf(Feb n);break;case 3:printf(Mar n);break;case 4:printf(Apr n);break;case 5:printf(May n);break;case

7、6:printf(Jun n);break;case 7:printf(Jul n);break;case 8:printf(Agu n);break;case 9:printf(Sep n);break;case 10:printf(Oct n);break;case 11:printf(Nov n);break;case 12:printf(Dec n);break;第5章1.(1) b (2) a (3) b (4) d (5) c2. 7,13. y=-14.m=65. 10,146. 37. 58. ABABCDCD9.x=8,y=2210.&n211.# include main

8、( ) int i;long int sum=0;for (i=2;i=200;i+=2)sum+=i;printf(2+4+6+.+200=%ld,sum);12.#include main()long int n;int sum = 0;printf(Please input the nber:);scanf(%ld,&n);while(n != 0) sum += n % 10;n /= 10;printf(%dn, sum);第6章1.(1) d (2) b (3) d (4) c 2. 113. 34. 56895. 12,66. i-n7. char k;ij8.#include

9、main( )float a10;int i;float sum=0,average;for (i=0;i10;i+)printf(a%d=?,i);scanf(%f,&ai);sum+=ai;average=sum/10;printf(average is %.2fn,average);9.#include #define N 10main( )int aN,i,target,found;for (i=0;iN;i+)scanf(%d,&ai);printf(Please input a number:);scanf(%d,&target);i=0;while(iN & target !=

10、ai)i+;found = iN?i:-1;printf(%dn,found);10.#include #define N 80main( )char strN;int len=0,i=0;printf(Please input a string:);gets(str);while (stri+ != 0) len+;printf(the length of string is %d.n,len);第7章1. 21 2. 1363. 164. func m+5. 96.1,6,3,2,37. 2,5,1,2,3,-28.#include int fun(int a,int b,int c);m

11、ain( )int a,b,c,max;printf(Please input three numbers:);scanf(%d%d%d,&a,&b,&c);max=fun(a,b,c);printf(Max is %d.n,max);int fun(int a,int b,int c)int max;max= ab?(ac?a:c):(bc?b:c);return max;9.#include long int sum(int n);main( )int n;printf(n=?);scanf(%d,&n);printf(Sum=%ld.n,sum(n);long int sum(int n

12、)if (n = = 1 ) return 1;else return sum(n-1)+n;10.#include void fun(n);main( )int n;printf(n=?);scanf(%d,&n);fun(n);void fun(n)if (n = = 0) return;elsefun(n/2);printf(%-2d,n%2);第8章1.(1) b (2) d (3) b (4) c (5) c2. 83. 1234567894. 2 3 4 5 65. 3456. 1 2 3 4 5 67. *(br+i)8. bcdefgha9. p=sum10.#include

13、#include main() char str80; char *p1, *p2;gets(str);p1=str;p2=str+strlen(str)-1; while (p1p2 & *p1+ = *p2- ) ;puts( p1p2 ? 不是回文 : 是回文 ); 第9章1.a. #define F(x) (x)*(x)*(x)b. #define F(x) (x)%4c. #define F(x,y) (x)*(y)100?1:02.a. 4b. 4c. #define DOUBLE(x) 2*(x)3. d4. -205. N is undefined6. 7.57. y=68.#

14、include #define SWAP(a,b) int temp;temp=a;a=b;b=temp;main()int x,y;printf(x=?);scanf(%d,&x);printf(y=?);scanf(%d,&y);SWAP(x,y)printf(x=%d,y=%d.n,x,y);第10章1.struct studentint sno;char sname10;char sex;stu1,stu2;2. 123. 合法的有a,b,d c.改成s.u.rectangle.length=25; e.改成 s.u.circle.radius=5; f.改成 s.u.circle.r

15、adius=5;4. a,b,c,d (说明：变量b 有确定的值之后，b+是合法的。)5. 改为typedef struct productchar name10;float price;PRODUCT;PRODUCT products10;6.struct employeeprintemp(emp)7. 2 4 3 9 88.#include struct time_structint hour;int minute;int second;main( )struct time_struct time;printf(Input time?n(Example 18:28:38)n);scanf(

16、%d:%d:%d,&time.hour,&time.minute,&time.second);printf(Time is %d:%d:%dn,time.hour,time.minute,time.second);9.#include struct time_structint hour;int minute;int second;time;void enter_time();void display_time();main( )enter_time();display_time();void enter_time()printf(Enter the time(example 18:28:38

17、)?);scanf(%d:%d:%d,&time.hour,&time.minute,&time.second);void display_time()printf(Time is %d:%d:%d.n,time.hour,time.minute,time.second);10.#include #define N 3struct hotelchar name31; /*旅馆名称*/char address31;/*旅馆地址*/int grade; /*旅馆级别*/float average_charge; /*平均房价*/int number; /*房间数量*/hN=h1,上海路,5,500

18、.00,80,h2,北京大街,5,480.00,70,h3,南京大街,3,300.50,100;main( )int grade,i;printf(请输入级别(3-5)?);scanf(%d,&grade);for (i=0;iN;i+)if (hi.grade=grade) printf(名称:%sn地址:%sn级别:%dn平均房价%.2fn房间数量:%dn,hi.name,hi.address,hi.grade,hi.average_charge,hi.number);第11章1. (1) c (2) d (3) b (4) b (5) b2. Basican3. fgetc(fp)4.

19、“record.dat”, “w”5. #include #include #include typedef struct Employeeint id;char name20;char gender20;int age;char address20;Employee;int main(void)FILE *fp;char another,choice;Employee emp;long int recsize;fp=fopen(employee.dat,rb+);if(fp=NULL)fp=fopen( employee.dat,wb+);if(fp=NULL)printf(Cant Ope

20、n File);exit(0);recsize=sizeof(emp);while(1)printf(1.添加记录 2.显示男员工 3.退出n);printf(Enter your choice(1-3):);fflush(stdin);scanf(%c,&choice);switch(choice)case1:fseek(fp,0,SEEK_END);another=Y;while(another=Y| another=y)printf(输入信息(id 姓名 性别 年龄 住址):n);scanf(%d %s %s %d %s,&emp.id,&emp.name,&emp.gender,&em

21、p.age,&emp.address);fwrite(&emp,recsize,1,fp);printf(是否继续 (Y/N): );fflush(stdin);another=getchar();break;case 2: printf(学号t姓名t性别t年龄t住址n);rewind(fp);while(fread(&emp,recsize,1,fp)=1) if (strcmp(emp.gender,男)=0) printf(%dt%st%st%dt%sn, emp.id,emp.name,emp.gender,emp.age,emp.address); break; case 3:fcl

22、ose(fp);exit(0);6.#includestdio.h#includestdlib.h#define M 2#define stu struct studentstuint num; char name20; float s1; float s2; float s3; float avg;main() stu stM;FILE *fp;int i; printf(请输入5名同学生的成绩，按照学号,姓名,成绩1,成绩2,成绩3的顺序,中间用空格隔开:n); for(i=0;iM;i+) scanf(%d%s%f%f%f,&sti.num,sti.name,&sti.s1,&sti.s

23、2,&sti.s3);sti.avg=(sti.s1+sti.s2+sti.s3)/3; if(fp=fopen(stud.rec,wb)=NULL) printf(cannot open filen); for(i=0;iM;i+) if(fwrite(&sti,sizeof(stu),1,fp)!=1) printf(file write errorn); fclose(fp); fp=fopen(stud.rec,rb); printf(numtnametscore1tscore2tscore3taveragen); for(i=0;iM;i+) fread(&sti,sizeof(st

24、u),1,fp);printf(%dt%st%.2ft%.2ft%.2ft%.2fn,sti.num,sti.name,sti.s1,sti.s2,sti.s3,sti.avg); fclose(fp);第12章1.a. 2 b. 4 c. 11 d. 4 e. -15 f. 28 g. -362.程序设计分析：先将整数x 右移4 位，将该整数机内码的第4 到7 位移至第0 到3 位，然后与0x000f(0000000000001111)进行位与运算，所保留的低4 位就是所要的结果#include void main()int x,y;scanf(%d,&x);y=x4; y=y&0x000f;printf(47位的十六进制数：y=%#xn,y);3. d4. p!=NULLp-next5. p-next6. 略