《C语言程序设计》(苏小红)课后习题答案高等教育出版社.doc

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)

#includeo.h>
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
4.1(1)
#include
main()
{
char c1='a',c2='b',c3='c';
printf("a%cb%cc%c\n",c1,c2,c3);
}

4.1(2)
#include
main()
{
int a=12,b=15;
printf("a=%d%%,b=%d%%\n",a,b);
}

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);
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))/(2a);
printf("x=%f,y=%f\n",x,y);
}
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)
{
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);
}
}
1

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 ifch>=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)
{
printf("%d--B\n",score);
}
else if(score>=70&&score<80)
{
printf("%d--C\n",score);
}
else if(score>=60&&score<70)
{
printf("%d--D\n",score);
}
else if(score>=0&&score<60)
{
printf("%d- -E\n",score);
}
}
5.10
#include
main()
{
int year,month;
printf("Input year,month:");
scanf("%d,%d",&year,&month);
if(month>12||month<=0)
{
printf("error month\n");
}
else
{
switch(year,month)
{
case 12:
case 10:
case 8:
case 7:
case 5:
case 3:
case 1:
printf("31 天\n");
break;
case 11:
case 9:
case 6:
case 4:
printf("30 天\n");
break;
case 2:
if(year%4==0&&year!=0||year%400==0)
{
printf("29 天\n");
}
else
{
printf("28 天\n");
}
break;
default:
printf("Input error\n");
}
}
}
6.1(1)
#include
main()
{
int i,j,k;
char space=' ';
for(i=1;i<=4;i++)
{
for(j=1;j<=i;j++)
{
printf("%c",space);
}
for(k=1;k<=6;k++)
{
printf("*");
}
printf("\n");
}
}
6.1(2) #include
main()
{
int k=4,n;
for(n=0;n
main()
{
int k=4n;
for(n=0;n
main()
{
int i,sum=0;
for(i=1;i<=101;i++)
{
sum=sum+i;
}
printf("sum=%d\n",sum);
}
6.2(2) #include
main()
{
long i;
long term,sum=0;
for(i=1;i<=101;i=i+2)
{
term=i*i+1)*(i+2);
sum=sum+term;
}
printf("sum=%ld\n",sum);
}
6.2(4) #include
#include
main()
{
int n=1;
float term=1.0,sign=1,sum=0;
while(term<=-1e-4||term>=1e-4)
{
term=1.0/sign;
sum=sum+term;
sign=sign+n;
n++;
}
printf("sum=%f\n",sum);
}
6.2(5) #include
#include
main()
{
int n=1,count=1;
float x;
double sum,term;
printf("Input x:");
scanf("%f",&x);
sum=x;
term=x;
do{
term=-term*x*x/((n+1)*(n+2));
sum=sum+term;
n=n+2;
count++;
}while(fabs(term)>=1e-5);
printf("sin(x)=%f,count=%d\n",sum,count);
}
6.3 #include
main()
{
int x=1,find=0;
while(!find)
{
if(x%2==1&&x%3==2&&x%5==4&&x%6==5&&x%7==0)
{
printf("x=%d\n",x);
find=1;
x++;
}
}
}
/* int x,find=0;
for (x=1;!find;x++)
{
if(x%2==1&&x%3==2&&x%5==4&&x%6==5&&x%7==0)
{
printf("x=%d\n",x);
find=1;
}
}
}*/
6.4 #include
main()
{
int in;
long p=1,m=1;
printf("Input n:");
scanf("%d",&n);
for(i=1;i<=n;i++)
{
p=i*i;
m=i*i*i;
printf("p=%d,m=%d\n",i,p,i,m);
}
}
6.5 #include
main()
{
float c,f;
for(c=-40;c<=110;c=c+10)
{
f=9/5*c+32;
printf("f=%f\n",f);
}
}
6.6 #include
#include
main()
{
int n;
double c=0.01875,x;
do{
x=x*pow(1+c,12)-1000;
n++;
}while(x>0);
printf("x=%d\n",x);
}
6.7 #include
main()
{
int n=0;
float a=100.0,c;
printf("Inputc:");
scanf("%f",&c);
do
{
a=a*(1+c);
n++;
}while(a<=200);
printf("n=%d\n",n);
}
6.8 #include
#include
main()
{
int n=1,count=1;
double sum=1,term=1;
while(fabs(term)>=1e-5)
{
term=pow(-1,count)*(1.0/(n+2));
sum=sum+term;
n=n+2;
count++;
}
sum=4*sum;
printf( "sum=%f,count=%d\n",sum,count);
}
6.9 #include
#include
main()
{
int n=1,count=1;
double sum=1,term=1;
while(fabs(term)>=1e-5)
{
term=term*(1.0/n);
sum=sum+term;
n++;
count++;
}
printf("sum=%f,count=%d\n",sum,count);
}
6.10 #include
#include
main()
{
int x;
for(x=100;x<=999;x++)
{
if(x==pow(x/100,3)+pow(x/10%10,3)+pow(x%10,3))
printf("x=%d\n",x);
}
}
6.11 #include
main()
{
int i=0,n;
long sum=0,term=1;
printf("Inputn:");
scanf("%d",&n);
do{
i++;
term=term*i;
sum=sum+term;
}while(sum
main()
{
int i,n,m,count=0,sum=0;
printf("Input n:");
scanf("%d",&n);
for(i=1;i<=n;i++)
{
printf("Inputm:");
scanf("%d",&m);
if(m>0)
{
sum=sum+m;
count++;
}
else
{
break;
}
printf("sum=%d,count=%d\n",sum,count);
}
}
6.13 #include
main()
{
int i,n,m,count=0,sum=0;
printf("Inputn:");
scanf("%d",&n);
for(i=1;i<=n;i++)
{
printf("Inputm:");
scanf("%d",&m);
if(m>0||m<0)
{
sum=sum+m;
count++;
}
else
{
break;
}
printf("sum=%d,count=%d\n",sum,count);
}
}
6.14 #include
main()
{
int x,y,z;
for(x=0;x<=17;x++)
{
for(y=0;y<=25;y++)
{
3*x+2*y+z==50;
z=30-x-y;
if( 3*x+2*y+z==50&&x+y+z==30)
printf("x=%d,y=%d,z=%d\n",x,y,z);
}
}
}
6.15 #include
main()
{
int x,y;
for(x=0;x<=98;x++)
{
y=98-x;
2*x+4*y==386;
if(x+y==98&&2*x+4*y==386)
{
printf("x=%d,y=%d\n",x,y);
}
}
}
6.16 #include
main()
{
int x,y,z;
for(x=0;x<=20;x++)
{
for(y=0;y<=33;y++)
{
3*y+5*x+z/3.0==100;
z=100-x-y;
if (5*x+3*y+z/3.0100&&z+x+y==100)
{
printf("x=%d,y=%d,z=%d\n",x,y,z);
}
}
}
}
6.17 #include
main()
{
int x,y,z;
for(x=1;x<=9;x++)
{
for(y=1;y<=17;y++)
{
10*x+5*y+z==100;
z=50-x-y;
if( 10*x+5*y+z==100&&x+y+z==50&&z>0)
{
printf("x=%d,y=%d,z=%d\n",x,y,z);
}
}
}
}
7.1 #include
int Square(int i)
{
return i*i;
}
int main()
{
int i=0;
i=Square(i);
for( ;i<3;i++)
{
static int i=1;
i+=Square(i);
printf("%d,",i);
}
printf("%d\n",i);
return 0;
}
7.2 #include
int hour,minute,second;
void update()
{
second++;
if(second==60)
{
second=0;
minute++;
}
if(minute==60)
{
minute=0;
hour++;
}
if(hour==24)
hour=0;
}
void display()
{
printf("%d,%d,%d\n",hour,minute,second);
}
void delay()
{
int t;
for(t=0;t<100000000;t++);
}
int main()
{
int i;
void updaye(),display(),delay();
for(i=0;i<1000000;i++)
{
update();
display();
delay();
}
return 0;
}
7.3 #include
int GetMax(int a,int b);
int main()
{
int x,y,max;
printf("Inputx,y:");
scanf("%d,%d",&x,&y);
max=GetMax(x,y);
printf("max=%d\n",max);
return 0;
}
int GetMax(int m,int n)
{
if(m>=n)
return m;
else
return n;
}
7.4 #include
int LCM(int n,int m);
int main()
{
int a,b;
printf("Inputa,b:");
scanf("%d,%d",&a,&b);
printf("%d\n",LCM(a,b));
return 0;
}
int LCM(int n,int m)
{
int x;
int find=0;
for(x=1;!find;x++)
{
if(x%n==0&&x%m==0)
{
find=1;
}
}
return x-1;
}
7.5 #include
long Fact(int n);
int main()
{
int m,a;
printf("Inputm:");
scanf("%d",&m);
for(a=1;a<=m;a++)
{
printf("%d!=%ld\n",a,Fact(a));
}
return 0;
}
long Fact(int n)
{
int i;
long result=1;
for(i=2;i<=n;i++)
result*=i;
return result;
}
7.6 #include
long Fact(int n);
int main()
{
int m;
long ret;
printf("Inputm:");
scanf("%d",&m);
ret=Fact(m);
printf("ret=%d\n",ret);
return 0;
}
long Fact(int n)
{
int i;
long result=1,sum=0;
for(i=2;i<=n;i++)
{
result*=i;
sum=sum+result;
}
return sum;
}
7.7(1) #include
int Gcd(int a,int b);
int main()
{
int m,n;
printf("Inputm,n:");
scanf("%d,%d",&m,&n);
printf("%d\n",Gcd(m,n));
return 0;
}
int Gcd(int a,int b)
{
int t,min,find=0;
min=a
int Gcd(int a,int b);
int main()
{
int m,n;
printf("Inputm,n:");
scanf("%d,%d",&m,&n);
printf("%d\n",Gcd(m,n));
return 0;
}
int Gcd(int a,int b)
{
int r,temp;
r=a%b;
if(r==0)
return b;
else
do{
temp=b;
b=r;
a=temp;
r=a%b;
}while(r!=0);
return b;
}
8.1(1) #include
void Func(int x)
{
x=2;
}
int main()
{
int x=10;
Func(x);
printf("%d",x);
return 0;
}
8.1(2) #include
void Func(int b[])
{
int j;
for(j=0;j<4;j++)
{
b[j]=j;
}
}
int main()
{
static int a[]={5,6,7,8},i;
Func(a);
for(i=0;i<4;i++)
{
printf("%d",a[i]);
}
return 0;
}
8.2(1) int PositiveNum(int a[],int n)
{
int i,count=0;
for(i=0;i0)
count++;
}
return 0;
}
8.2(2) void Fib(long f[],long n)
{
int i;f[0]=0;
f[1]=1;
for(i=2;i
int main()
{
int a[10],n,max,min,maxPos,minPos;
for(n=0;n<10;n++)
{
scanf("%d",&a[n]);
}
max=min=a[0];
maxPos=minPos=0;
for(n=0;n<10;n++)
{
if(a[n]>max)
{
max=a[n];
maxPos=n;
}
else if(a[n]i++)
{
pArray[i]/=pAttay[0];
}
}
8.4 #include
#define N 40
int FailNum(int score[],int n);
void ReadScore(int score[],int n);
int main()
{
int score[N],n;
printf("Input n:");
scanf("%d",&n);
ReadScore(score,n);
FailNum(score,n);
printf("FailNum students are %d\n",FailNum(score,n));
return 0;
}
int FailNum(int score[],int n)
{
int i,count=0;
for(i=0;i
#define N 40
int HighAver(int score[],int n);
int ReadScore(int score[]);
int main()
{
int score[N],n;
n=ReadScore(score);
printf("HighAver students are %d\n",HighAver(score,n));
return 0;
}
int HighAver(int score[],int n)
{
int i,count=0,sum=0,aver;
for(i=0;i/n;
}
for(i=0;iaver)
count++;
}
return count;
}
int ReadScore(int score[])
{
int i=-1;
do{
i++;
printf("Input score:");
scanf("%d",&score[i]);
}while(score[i]>=0);
return i;
}
8.6 #include
#define N 40
int ReadScore(int score[],long num[]);
int FindMax(int score[],long num[],int n);
int main()
{
int score[N],n,max,num,t;
long num[N];
t=FindMax(score,n);
max=score[t];
num=num[t];
printf("max=%d,num=%d\n",max,num);
return 0;
}
int ReadScore(int score[],long num[])
{
int i=-1;
do{
i++;
printf("Input student's ID and score:");
scanf("%ld%d",&num[i],&score[i]);
}while(num[i]>0&&score[i]>=0);
return i;
}
int FindMax(int score[],long num[],int n)
{
int max,i;
max=score[0];
for(i=1;imax)
max=score[i];
}
return i;
}
8.7 #include
#define N 40
int Read(int a[]);
int ChangeArry(int a[],int n);
int main()
{
int a[N],n;
printf("%d\n",ChangeArry(a,n));
return 0;
}
int Read(int a[])
{
int i;
for(i=0;i<9;i++)
{
printf("Input a:");
scanf("%d",&a[i]);
return i;
}
int ChangeArry(int a[],int n)
{
int max,min,i,maxpos,minpos,term;
max=min=score[0];
for(i=1;i{
if(a[i]>max)
max=score[i];
maxpos=n;
else(a[i]
#define N 5
void main()
{
int a[N][N];
int sum = 0;
int i, j;
printf("请输入一个%d*%d 的矩阵\n",N,N);
for(i = 0; i < N; i++)
{
forj = 0; j < N; j++)
{
scanf("%d",&a[i][j]);
}
}
for(i = 0; i < N; i++)
{
for(j = 0; j < N; j++)
{
if(i == j || i + j == N - 1)
sum=sum+a[i][j];
}
}
printf("对角线元素之和为：%d\n",sum);
}
8.11 #include
#define N 2
#define M 3
void main()
{
int a[N][M],b[N][M];
int i,j,sum1=0,sum