c语言作业答案第四章,c语言程序设计课习题答案 第四章.doc

c语言程序设计课习题答案 第四章

/*习题4 4*/

#include

main()

{

int x1,x2,i,n,x;

double item,sum;

printf("enter n:\n");

scanf("%d",&n);

x1=2;x2=1;

sum=0;

for(i=1;i<=n;i++)

{

item=1.0*x1/x2;

sum=sum+item;

x=x1+x2;

x2=x1;

x1=x;

}

printf("sum=%.2lf\n",sum);

}

/*练习4-3*/

#include

#include

main()

{ int a=-1,t=-2;

double eps,s=0,item=1;

printf("enter eps:\n");

scanf("%lf",&eps);

while(fabs(item)>=eps)

{

t=t+3;

a=-a;

item=a*1.0/t;

s=s+item;

}

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

}

/*练习4-3*/

#include

main()

{ int n=-1,bujige=-1;

double grade=0,sum=0,ave;

printf("enter grade:\n");

while(grade>=0)

{

sum=sum+grade;

if(grade<60)

bujige=bujige+1;

n=n+1;

scanf("%lf",&grade);

}

ave=sum/n;

printf("ave=%lf\n",ave);

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

}

/*练习4-4*/

#include

main()

{ int n=-1,bujige=-1;

double chengji=0,sum=0,ave;

printf("enter n ge zheng zheng shu \n");

while(chengji>=0)

{

sum=sum+chengji;

n++;

if(chengji>=0&&chengji<=60)

bujige=bujige+1;

scanf("%lf",&chengji);

}

ave=sum/n;

printf("ave=%lf\n",ave);

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

}

/*练习4-7*/

#include

main()

{ int n,i,j,m;

printf("enter zheng zheng shu n:\n");

scanf("%d",&n);

printf("enter n ge zheng zheng shu:\n");

for(i=1;i<=n;i++)

{scanf("%d",&m);

if(m==1)

printf("1 bu shi su shu \n");

else

{ for(j=2;j<=m/2;j++)

if(m%j==0)

break;

if(j>m/2)

printf("%d shi su shu\n",m);

else

printf("%d bu shi su shu\n",m);

}

}

}

/*练习4-8*/

#include

main()

{ int n,i,j,jiecheng;

double sum=0;

printf("enter yi ge zheng zheng shu n:\n");

scanf("%d",&n);

for(i=1;i<=n;i++)

{ jiecheng=1;

for(j=1;j<=i;j++)

jiecheng=jiecheng*j;

sum=sum+1.0/jiecheng;

}

printf("e=%.2lf\n",sum+1);

}

/*练习4-11*/

#include

main()

{ int n,mark,i,min;

printf("enter yi ge zheng