全国计算机等级考试二级教程--C语言程序设计课后习题答案.doc

《全国计算机等级考试二级教程--C语言程序设计》课后习题答案

第一章
1.1 EXE
1.2 C OBJ EXE
1.3 顺序 选择 循环

第二章
一. 选择题
2.1 B 2.2 D 2.3 B 2.4 A 2.5 C 2.6 A 2.7 B
2.8 B 2.9 D 2.10 C 2.11 B 2.12 B 2.13 A
二. 填空题
2.14 11 12
2.15 4.2 4.2
2.16 { } 定义 执行语句
2.17 关键字 用户标识符
2.18 int float double
2.19 float a1=1; float a2=1;
2.20 存储单元
2.21 3.5
2.22 (a*b)/c a*b/c a/c*b
2.23 把常量10赋给变量s
2.24 位 1或0
2.25 8 127 0111111 -128 10000000
2.26 32767 -32768 1000000000000000
2.27 10 8 16
三. 上机改错题
2.28
#include "stdio.h"; 删除行尾的";"
main(); / * main function * / 删除")"后的";",注释中的*要紧靠“/”,即应为“/*”和“*/”
函数开始处遗失了一个“{”
float r,s ; /*/*r is radius*/,/* s is area of circuilar*/*/ 注释符号不可嵌套使用
r = 5.0 ;
s = 3.14159 * r * r ;
printf("%f\n",s) 行尾遗失了“;”
函数结束处遗失了一个“}”

2.29
#include "stdio.h"
main /* main function */ main后遗失了“()”
{
float a,b,c,v; /*a,b,c are sides, v is volume of cube */
a=2.0; b=3.0; c=4.0 行尾遗失了“;”
v=a*b*c;
printf("%f\n", v) 行尾遗失了“;”
}

第三章
一. 选择题
3.1 C 3.2 C 3.3 D 3.4 C 3.5 D 3.6 B 3.7 C 3.8 D 3.9 A 3.10 B
3.11 C 3.12 D 3.13 D 3.14 A 3.15 C 3.16 C 3.17 C 3.18 无答案 3.19 C 3.20 B

二. 填空题
3.21 (1)-2002500(2)i=-200,j=2500
(3)i=-200
j=2500
3.22 12 0 0
3.23 一条语句 ;
3.24 ;
3.25 100,25.81,1.89234 100 25.81 1.89234 100 25.81 1.89234
3.26 x=127,x= 127,x= 177,x= 7f,x= 127
3.27 x=127,x=127 ,x=$127 ,x=$000127,x=%06d
3.28 a=513.789215,a= 513.79,a= 513.78921500,a= 513.78921500

三. 编程题和改错题
3.29 修改后的程序如下：
main()
{
double a,b,c,s,v;
printf("input a,b,c:");
scanf("%lf%lf%lf",&a,&b,&c);
s =a*b;
v=a*b*c;
printf("a=%f,b=%f,c=%f\n", a,b,c);
printf("s=%f,v=%f\n",s,v);
}
3.30
#include
main()
{
int a=560,b=60;
printf("560 minute is %d hour and %d minute.\n",a/b,a%b);
}
3.31
#include
main()
{
int a,b;
a=1500;b=350;
printf("a div b is : %d\n",a/b);
printf("a mod b is : %d\n",a%b);
}
3.32
#include
main()
{
double a,b,c,ave;
printf ("input 3 double number : \n");
scanf ("%lf%lf%lf",&a,&b,&c);
printf ("%.1f\n",(a+b+c)/3);
}
3.33
#include
void main()
{
int a,b,c,t;
printf("请依次输入整数a,b,c:");
scanf("%d%d%d",&a,&b,&c);
printf("\n你输入的值是: a=%d,b=%d,c=%d\n",a,b,c);
t=b;b=a;a=c;c=t;
printf("交换之后的值是:a=%d,b=%d,c=%d\n",a,b,c);
}

第四章
一. 选择题
4.1 A 4.2 A 4.3 A 4.4 D 4.5 C 4.6 A 4.7 B 4.8 C 4.9 D 4.10 C
二. 填空题
4.11 非0 0
4.12 < > >= <=同级 == ！=同级
4.13 ! && ||
4.15 !
4.16 a == b || a < c x > 4 || x < -4
4.17 1
4.18 x <= 0 1 > 0
4.19 3 2 2
4.20 *#

三. 编程题
4.21 略
4.22
#include

/* 检查日期的合法性 */
int checkdate(int year, int month, int day)
{
if(year < 1900 || year > 2005)
{
printf("输入的年份无效!\n");
return 0;
}
else if(month < 0 && month > 12)
{
printf("输入的月份无效!\n");
return 0;
}
else if(day <= 0 && day > 31)
{
printf("输入的日期无效!\n");
return 0;
}
else
{
switch(month)
{
case 4:
case 6:
case 9:
case 11:
if(day > 30)
{
printf("输入的日期无效!\n");
return 0;
}
break;
case 2:
if((year%4 == 0 && year%100 != 0) || year%400 == 0)
{
if(day > 29)
{
printf("输入的日期无效!\n");
return 0;
}
}
else
{
if(day > 28)
{
printf("输入的出生日期无效!\n");
return 0;
}
}
break;
}/* end of switch(m0)*/
}
return 1;
}

void main()
{
int y0, m0, d0; /* 生日 */
int y1, m1, d1; /* 当前日期 */
int years, months, days; /* 实足年龄*/

printf("请输入学生的生日:");
scanf("%d%d%d", &y0,&m0,&d0);

if(checkdate(y0, m0, d0))
{
printf("请输入当前日期:");
scanf("%d%d%d", &y1,&m1,&d1);
/*当前日期合法性检查*/
if(!checkdate(y1, m1, d1))
{
return;
}
else if(y0 > y1)
{
printf("出生年份比当前年份晚!\n");
return;
}
else if(y0 == y1)
{
if(m0 > m1)
{
printf("出生年月比当前年月晚!\n");
return;
}
else if(m0 == m1)
{
if(d0 > d1)
{
printf("出生年月日比当前年月日晚!\n");
return;
}
}
}
}

/* 计算实足年龄 */
years = y1 - y0;
months = m1 - m0;
days = d1 - d0;

/* 修正实足年龄天数*/
if(days < 0)
{
months--;
switch(m1)
{
case 1:
case 5:
case 7:
case 10:
case 12:
days += 30;
break;
case 2:
case 4:
case 6:
case 8:
case 9:
case 11:
days += 31;
break;
case 3:
if((y1%4 == 0 && y1%100 != 0) || y1%400 == 0)
{
days += 29;
}
else
{
days += 28;
}
break;
}/* end of switch(m1) */

}/* end of if(days < 0) */

/* 修正实足年龄月数*/
if(months < 0)
{
months += 12;
years--;
}/* end of if(months < 0) */

printf("出生日期: %d年%d月%d日\n", y0, m0, d0);
printf("当前日期: %d年%d月%d日\n", y1, m1, d1);
printf("实足年龄: %d年%d月%d日\n", years, months, days);

return;
}

4.23
#include

void main()
{
int a;
printf ("请输入一个整数 :");
scanf ("%d",&a);
if (a%2==0)
{
printf ("%d 是偶数\n", a);
}
else
{
printf ("%d 是奇数\n", a);
}
}

4.24
#include

void main()
{
int a,b,c,temp,max;
printf ("请输入三个整数 :");
scanf ("%d %d %d",&a,&b,&c);
temp=(a>b)? a:b;
max=(temp>c)? temp:c;
printf ("\n");
printf ("你输入的数中最大的是 %d.\n",max);
}

4.25
(1)不嵌套的if语句
#include

void main()
{
int x,y;
printf("input x :");
scanf("%d",&x);
if ( x>-5 && x<0 )
{
printf("y is %d\n",y=x);
}
if ( x==0 )
{
printf("y is %d\n",y=x-1);
}
if ( x>0 && x<10 )
{
printf("y is %d\n",y=x+1);
}
if ( x>=10 || x<=-5)
{
printf("error\n");
}
}
(2)嵌套的if语句
#include

void main()
{
int x,y;
printf("input x :");
scanf("%d",&x);
printf("\n");
if(x < 0)
{
if(x > -5)
{
printf("y is %d.\n",y=x);
}
else
{
printf("error!\n");
}
}
if(0 == x)
{
printf("y is %d.\n",y=x-1);
}
if(x > 0)
{
if(x < 10)
{
printf("y is %d.\n",y=x+1);
}
else
{
printf("error!\n");
}
}
}
(3)if_else语句
#include

void main()
{
int x,y;
printf("input x :");
scanf("%d",&x);
if( x>-5 && x<0 )
{
printf("y is %d.\n",y=x);
}
else if( x==0 )
{
printf("y is %d.\n",y=x-1);
}
else if( x>0 && x<10 )
{
printf("y is %d.\n",y=x+1);
}
else
{
printf("error!\n");
}
}
(4)switch语句
#include

void main()
{
int x,y;
printf("input x : ");
scanf("%d",&x);
switch (x)
{
case -4:
case -3:
case -2:
case -1:
printf("y is %d.\n",y=x);
break;
case 0:
printf("y is %d.\n",y=x-1);
break;
case 1:
case 2:
case 3:
case 4:
case 5:
case 6:
case 7:
case 8:
case 9:
printf("y is %d.\n",y=x+1);
break;
default:
printf("error!\n");
}
}

第五章

一. 选择题
5.1 D 5.2 C 5.3 B 5.4 C 5.5 C 5.6 B 5.7 D 5.8 A 5.9 D 5.10 D

二. 填空题
5.11 5 4 6
5.12 死循环
5.13 -1
5.14 11
5.15 d=1.0 k++ k<=n
5.16 x>=0 x
三. 编程题
5.17
#include
void main()
{
int i;
int sig = 1;
int sum = 0;
for(i=1; i<=101; i++,i++)
{
sum += sig*i;
sig *= -1;
}
printf("sum=%d\n", sum);
}

5.18
(1)
#include

void main()
{
int i;
double m=1.0;
double e = 1.0;
for(i=1; i<50; i++)
{
m *= i;
e += 1/m;
}
printf("e=%f\n",e);
}
(2)
#include

void main()
{
int i=1;
double m=1.0;
double e = 1.0;
while(1/m >= 0.0004)
{
m *= i;
e += 1/m;
i++;
}
printf("e=%f\n",e);
}

5.19
#include

void main()
{
int year;
int col = 0;
for(year=1600; year<=2000; year++)
{
if((year%4 == 0 && year%100 != 0) || year%400 == 0)
{
printf("%d\t", year);
col++;
if(col%5 == 0)
{
printf("\n");
}
}
}
printf("\n");
}

5.20
#include
#define N 7

void main()
{
int i;
int j;
int m;
int k = N/2;
for(i=0; i {
m = i-k;
if(m < 0)
{
m *= -1;
}
for(j=0; j {
printf(" ");
}
for(j=0; j<2*(k-m)+1; j++)
{
printf("*");
}
printf("\n");
}
}

第六章

一. 选择题
6.1 B 6.2 D 6.3 A 6.4 A 6.5 B 6.6 D 6.7 D 6.8 B 6.9 A 6.10 A 6.11 C

二. 填空题
6.12 -1
6.13 1
6.14 ctype.h
6.15 1
6.16 10A 20B 30C 40D
6.17 7.29 101.298AB
6.18 A7.29B101.298
6.19 A B C (每个字符后有三个空格)

三. 编程题
6.20
#include
#define N 80

void main()
{
char str[N];
int iLoop = 0;
gets(str);
while(str[iLoop])
{
printf("%c-%d\t", str[iLoop],str[iLoop]);
iLoop++;
if(iLoop%3 == 0)
{
printf("\n");
}
}
printf("\n");
}

6.21
#include
#define N 80

void main()
{
char str[N];
int num = 0;
int iLoop = 0;
gets(str);
while(str[iLoop])
{
if(str[iLoop] >= '0' && str[iLoop] <= '9')
{
num = 10*num + (str[iLoop] - '0');
}
iLoop++;
}
printf("%d\n",num);
}

6.22
#include
#include
#define N 80

void main()
{
char str[N];
int num = -1;
do
{
gets(str);
num++;
}while(strcmp(str, "EOF"));
printf("您输入了%d行字符！\n",num);
}

6.23
#include
#define N 80

void main()
{
char str[N];
int iLoop = 0;
int num = 0;
gets(str);
while(str[iLoop] && iLoop < N)
{
if(str[iLoop] >= 'a' && str[iLoop] <= 'z')
{
num++;
}
iLoop++;
}
printf("您输入了字符中有%d个小写字母！\n",num);
}

6.24
#include

void main()
{
int line;
int iLoop1;
int iLoop2;

printf("请输入图案的行数(不大于26):");
scanf("%d", &line);
for(iLoop1 = 0; iLoop1 < line; iLoop1++)
{
for(iLoop2 = 0; iLoop2 < line - iLoop1; iLoop2++)
{
printf(" ");
}
for(iLoop2 = 0; iLoop2 < 2*iLoop1+1; iLoop2++)
{
printf("%c",iLoop1 + 'A');
}
printf("\n");
}
}

第七章

一. 选择题
7.1 C 7.2 C 7.3 B 7.4 C 7.5 A 7.6 D 7.7 A

二. 填空题
7.8 12
7.9 9.000000
7.10 4
7.11 n=1 s
7.12 <=y z*x
7.13 1 s*i 0 f(k)

三. 程序调试和编程题
7.14
fun(int n)
{ int k,yes;
for(k=2; k<=n/2; k++)
{
if(n%k == 0) { yes = 0; break;}
else yes = 1;
}
return yes;
}
7.15
int mymod(int a, int b)
{
return a%b;
}
7.16
double fun(int n)
{
double sum = 0;
int iLoop;
int sig = -1;
for(iLoop=1; iLoop<=n; iLoop++)
{
sig *= -1;
sum += sig*1.0/iLoop;
}
return sum;
}
7.17
double fun(int n)
{
double t = 1.0;
int iLoop;
long tmp;
for(iLoop=2; iLoop<=n; iLoop++)
{
tmp = iLoop*iLoop;
t -= 1.0/tmp;
}
return t;
}
7.18
#include
#include

double fun(double x)
{
return x*x + 5*x + 4;
}

void main()
{
int x = 2;
printf("y1=%f\n", fun(x));
printf("y2=%f\n", fun(x+15));
printf("y3=%f\n", fun(sin(x)));
}

第八章
一. 选择题
8.1 A 8.2 B 8.3 B 8.4 C 8.5 B 8.6 B 8.7 C 8.8 D 8.9 B 8.10 C 8.11 C 8.12 C

二. 填空题
8.13 110
8.14 7 1
8.15 (1)char *p=&ch; (2) p=&ch; (3)scanf("%c",p); (4)*p='A'; (5)printf("%c",*p);
8.16 (1)s=p+3; (2)s=s-2 (3)50 (4)*(s+1) (5)2 (6)10 20 30 40 50

三. 编程题
8.17
void fun(double x, double y, double *sum, double *div)
{
*sum = x + y;
*div = x - y;
return;
}
8.18
void fun(double x, double y, double z, double *max, double *min)
{
*max = x;
*min = x;
if(*max < y)
{
*max = y;
}
if(*max < z)
{
*max = z;
}
if(*min > y)
{
*min = y;
}
if(*min > z)
{
*min = z;
}
return;
}

第九章
一. 选择题
9.1 D 9.2 A 9.3 A 9.4 C 9.5 C 9.6 A 9.7 B 9.8 D 9.9 C 9.10 C
9.11 C 9.12 D 9.13 D 9.14 A 9.15 A 9.16 A 9.17 C 9.18 C

二. 填空题
9.19 9 0
9.20 6
9.21 12
9.22 3
9.23 2721
9.24 -850,2,0
9.25 k=p k
9.26 (c=getchar()) c-'A'

三. 编程题
9.27
#include
#define N 81
int main()
{
int counter[10] = {0};
int iLoop = 0;
char str[N];

gets(str);
while(str[iLoop])
{
if(str[iLoop] >= '0' && str[iLoop] <= '9')
{
counter[str[iLoop] - '0']++;
}
iLoop++;
}
for(iLoop=0; iLoop < 10; iLoop++)
{
printf("%d - %d\n", iLoop, counter[iLoop]);
}
return 0;
}
9.28
void fun(int array[], int arraysize, int start)
{
int iLoop;
if(start < arraysize-1)
{
if(start <=0)
{
start = 1;
}
for(iLoop = start; iLoop < arraysize; iLoop++)
{
array[iLoop-1] = array[iLoop];
}
}
for(iLoop = 0; iLoop < arraysize; iLoop++)
{
printf("No.%d = %d\n", iLoop, array[iLoop]);
}
}
9.29
int fun(int arry1[], int arry2[], int arrysize)
{
int iLoop;
int counter = 0;
for(iLoop = 0; iLoop < arrysize; iLoop++)
{
if(arry1[iLoop] % 2)
{
arry2[counter++] = arry1[iLoop];
}
}
return counter;
}
9.30
void fun(char array[], int arraysize)
{
int iLoop1;
int iLoop2;
char temp;
/* 冒泡排序 */
for(iLoop1 = 0; iLoop1 < arraysize - 1; iLoop1++)
{
for(iLoop2 = 0; iLoop2 < arraysize - 1 - iLoop1; iLoop2++)
{
if(array[iLoop2] < array[iLoop2 + 1])
{
temp = array[iLoop2];
array[iLoop2] = array[iLoop2 + 1];
array[iLoop2 + 1] = temp;
}
}
}
}
9.31
#include

void fun(int array[], int arraysize, int inertNumber)
{
int iLoop;
int iLoop2;
if(array[0] < array[arraysize-1])
{
for(iLoop = 0; iLoop< arraysize; iLoop++)
{
if(array[iLoop] > inertNumber)
{
for(iLoop2 = arraysize - 1; iLoop2 >= iLoop; iLoop2--)
{
array[iLoop2 + 1] = array[iLoop2];
}
array[iLoop] = inertNumber;
break;
}
}
if(iLoop >= arraysize)
{
array[arraysize] = inertNumber;
}
}
else
{
for(iLoop = 0; iLoop< arraysize; iLoop++)
{
if(array[iLoop] < inertNumber)
{
for(iLoop2 = arraysize - 1; iLoop2 >= iLoop; iLoop2--)
{
array[iLoop2 + 1] = array[iLoop2];
}
array[iLoop] = inertNumber;
break;
}
}
if(iLoop >= arraysize)
{
array[arraysize] = inertNumber;
}
}
}

int main()
{
int iLoop;
int a[20] = {7,6,5,3,2,1};
for(iLoop = 0; iLoop < 6; iLoop++)
{
printf("%d ", a[iLoop]);
}
printf("\n");
fun(a, 6, 0);
for(iLoop = 0; iLoop < 7; iLoop++)
{
printf("%d ", a[iLoop]);
}
printf("\n");
fun(a, 7, 4);
for(iLoop = 0; iLoop < 8; iLoop++)
{
printf("%d ", a[iLoop]);
}
printf("\n");
fun(a, 8, 8);
for(iLoop = 0; iLoop < 9; iLoop++)
{
printf("%d ", a[iLoop]);
}
printf("\n");
return 0;
}
9.32
int fun(int number, int array[])
{
int iLoop = 0;
int iLoop2;
int binLen;
int midNumber;
int div;
int remain;

midNumber = number;
do
{
div = midNumber/2;
remain = midNumber%2;
midNumber = div;
array[iLoop++] = remain;
}while(midNumber);

binLen = iLoop;

for(iLoop2 = 0, iLoop = binLen - 1; iLoop2 < iLoop; iLoop2++, iLoop--)
{
midNumber = array[iLoop2];
array[iLoop2] = array[iLoop];
array[iLoop] = midNumber;
}
return binLen;
}
9.33
#include
#include
#define N 15

void fun(int array[], int arraysize)
{
int x;
int iLoop;
int iLoop2;

for(iLoop = 0; iLoop < arraysize; iLoop++)
{
iLoop2 = 0;
x = rand()%20;
do
{
if(x == array[iLoop2] && iLoop > 0)
{
x = rand()%20;
iLoop2 = 0;
}
iLoop2++;
}while(iLoop2 < iLoop);
array[iLoop] = x;
}
}

int main()
{
int a[N];
int iLoop;

fun(a, N);
for(iLoop = 0; iLoop < N; iLoop++)
{
printf("%d\n", a[iLoop]);
}
return 0;
}

第十章
一. 选择题
10.1 C 10.2 B 10.3 C 10.4 B 10.5 C 10.6 A 10.7 C 10.8 A 10.9 C 10.10 C

二. 填空题
10.11 GFEDCB
10.12 XYZ
10.13 SO
10.14 10
10.15 Itis
10.16 strlen(str)-1 j--
10.17 3
10.18 goodgood！

三. 编程题
10.19
char* mygets(char *str)
{
int iLoop = 0;
char ch;
while((ch=getchar()) != '\n')
{
str[iLoop++] = ch;
}
str[iLoop] = '\0';
return str;
}
char * m