高等教育出版社《C语言程序设计(苏小红)》课后习题答案

1

2.2 #include

main()

{

float x=2.5,y=2.5,z=2.5;

printf("x=%f\n",x);

printf("y=%f\n",y);

printf("z=%f\n",z);

}

3.1(1)

#include

main()

{

int a=12,b=3;

float x=18.5,y=4.6;

printf("%f\n",(float)(a*b)/2);

printf("%d\n",(int)x%(int)y);

}

3.1(2)

#include

main()

{

int x=32,y=81,p,q;

p=x++;

q=--y;

printf("%d %d\n",p,q); printf("%d %d\n",x,y); }

3.2

#include

main()

{

int x,b0,b1,b2,s;

printf("Inputx:");

scanf("%d",&x);

b2=x/100;

b1=(x-b2*100)/10;//或(x%100)/10;或x/10%10; b0=x%10;

s=b0*100+b1*10+b2;

printf("s=%d\n",s);

}

3.3

#include

#include

main()

{

float rate=0.0225;

float n,capital,deposit;

printf("Input n,capital:");

scanf("%f,%f",&n,&capital);

deposit=capital*pow(1+rate,n);

printf("deposit=%f\n",deposit);

}

3.4

#include

#include

main()

{

float a, b, c;

double x, y;

printf("Input a, b, c:");

scanf("%f %f %f", &a, &b, &c);

x=(-b+sqrt(b*b-4*a*c))/(2*a);

y=(-b-sqrt(b*b-4*a*c))/(2*a);

printf("x=%f,y=%f\n",x,y);

}

习题4 Array 4.1(1)

#include

main()

{

char c1='a',c2='b',c3='c';

printf("a%cb%cc%c\n",c1,c2,c3);

}

4.1(2)

main()

{

int a=12,b=15;

printf("a=%d%%,b=%d%%\n",a,b);

}

2

4.1(3)

#include

main()

{

int a,b;

scanf("%2d%*2s%2d",&a,&b);

printf("%d,%d\n",a,b);

}

4.2

#include

main()

{

long a,b;

float x,y;

scanf("%d,%d\n",&a,&b);

scanf("%f,%f\n",&x,&y);

printf("a=%d,b=%d\n",a,b);

printf("x=%f,b=%f\n",x,y);

}

5.1

#include

main()

{

float a;

printf("Input a:");

scanf("%f",&a);

if(a>=0)

{

a=a;

printf("a=%f\n",a);

}

else

{

a=-a;

printf("a=%f\n",a);

}

}

5.2

#include

main()

{

int a;

printf("Input a:");

scanf("%d", &a);

3

if(a%2==0)

{

printf("a是偶数");

}

else

{

printf("a是奇数");

}

}

5.3

#include

#include

main()

{

float a,b,c,s,area;

printf("Input a, b, c:");

scanf("%f %f %f", &a, &b, &c);

if(a+b>c&&a+c>b&&b+c>a)

{

s=(a+b+c)/2;

area=(float)sqrt(s*(s-a)*(s-b)*(s-c));

printf("area=%f\n",area);

}

else

{

printf("不是三角形");

}

}

5.4

#include

#include

main()

{

float a,b,c,x,y;

printf("Inputa,b,c:");

scanf("%f,%f,%f",&a,&b,&c);

if(a==0)

{

printf("该方程不是一元二次方程\n");

}

if(b*b-4*a*c>0)

{

x=(-b+sqrt(b*b-4*a*c))/(2*a);

y=(-b-sqrt(b*b-4*a*c))/(2*a);

printf("x=%f,y=%f\n",x,y);

4

}

else if(b*b-4*a*c==0)

{

x=-b/(2*a);

y=-b/(2*a);

printf("x=%f,y=%f\n",x,y);

}

else

{

printf("该方程无实根\n");

}

}

5.5

#include

main()

{

int year,flag;

printf("Input a year:");

scanf("%d",&year);

if(year%4==0&&year%400!=0||year%400==0)

{

flag=1;

}

else

{

flag=0;

}

if(flag==1)

{

printf("%d is a leap year!\n",year);

}

else

{

printf("%d is not a leap year!\n",year);

}

}

5.6

#include

main()

{

int year,flag;

printf("Input a year:");

scanf("%d",&year);

flag=year%400==0||year%4==0&&year%100!=0?1:0;

if(flag==1&&flag!=0)

5

{

printf("%d is a leap year!\n",year);

}

else

{

printf("%d is not a leap year!\n",year);

}

}

5.7

#include

main()

{

char ch;

printf("Inputch:");

scanf("%c",&ch);

if(ch>='a'&&ch<='z')

{

ch=getchar();

ch=ch-32;

printf("%c,%d\n",ch,ch);

}

else if(ch>='A'&&ch<='Z')

{

ch=getchar();

ch=ch+32;

printf("%c,%d\n",ch,ch);

}

else

{

printf("%c",ch);

}

}

6

5.8

#include

main()

{

char ch;

printf("Inputch:");

scanf("%c",&ch);

if(ch>=48&&ch<=57)

{

printf("ch是数字字符\n");

}

else if(ch>=65&&ch<=90)

{

printf("ch是大写字母\n");

}

else if(ch>=97&&ch<=122)

{

printf("ch是小写字母\n");

}

else if(ch==32)

{

printf("ch是空格\n");

}

else

{

printf("ch是其他字符\n");

}

}

5.9

#include

main()

{

int score,grade;

printf("Input score:");

scanf("%d",&score);

grade=score/10;

if(score<0||score>100)

{

printf("Input error\n");

}

if(score>=90&&score<=100)

{

printf("%d--A\n",score);

}

else if(score>=80&&score<90)

{

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printf("%d--B\n",score);

}

else if(score>=70&&score<80)

{

printf("%d--C\n",score);

}

else if(score>=60&&score<70)

{

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