C Primer Plus 第六版 章节课后编程练习答案（上）

下面的是C Primer Plus 第六版所有章节的课后编程练习的答案，是博主在学习过程中自己编写的，希望能和大家共同讨论，一起进步
PS：小伙伴们可以直接从左边的目录看自己需要的章节哟

第二章

2.1

#include 
int main(void)
{ 
    printf("Gustav Mahler\n");
    printf("Gustav\nMahler\n");
    printf("Gustav ");printf("Mahler\n");

    return 0;
} 

2.2

#include 
int main(void)
{
printf("姓名\n地址\n");
return 0; 
} 

2.3

#include 
int main(void)
{
    int oldyears;
    printf("请输入您的年龄（如19）\n");
    scanf("%d",&oldyears);
    printf("嘻嘻嘻(●'_'●)\n");
    printf("所以您%d岁惹，并且至少已经活了%d天\n",oldyears,oldyears*365);
    return 0;
}

2.4

#include 
void jolly(void);
void deny(void); 
int main(void)
{ 
    jolly();
    jolly();
    jolly();
    deny();
    return 0;
} 
void jolly(void)
{
    printf("For he's a jolly good fellow!\n");
}
void deny(void)
{
    printf("Which nobody can deny!\n");
}

2.5

#include 
void br(void);
void ic(void);
int main(void)
{ 
    br();
    ic();
    ic();
    printf("Brazil,Russia\n");

    return 0;
} 
void br(void)
{
    printf("Brazil,Russia,");
}
void ic(void)
{
    printf("India,China\n");
}

2.6

#include .h>
void smile();
int main(void)
{
    smile();
    smile();
    smile();
    printf("\n");
    smile();
    smile();
    printf("\n");
    smile();
    printf("\n");
    return 0; 
} 
void smile(void)
{
    printf("smile!");
} 

2.7

#include 
void one_three(void);
void two(void);
int main(void)
{ 
    printf("starting now:\n");
    one_three();
    printf("done!\n"); 
    return 0;
} 
void one_three(void)
{
    printf("one\n");
    two();
    printf("three\n");
}
void two(void)
{
    printf("two\n");
}

第三章

3.2

#include 
int main(void)
{ 
char ascii66;

printf("请输入一个ASCII码值(0-127)：");
printf("___\b\b\b") ;
scanf("%d",&ascii66);
printf("您刚刚输入的ASCII值是%d，对应的字符是%c\n",ascii66,ascii66); 

return 0;
}

3.3

#include 
int main(void)
{ 
printf("Startled by the sudden sound,Sally shouted,\n");
printf("\"By the Great Pumpkin,what was that!\"\n"); 

return 0;
}

3.4

#include 
int main(void)
{ 
float f_scan;

printf("Enter a floating-point value:");
scanf("%f",&f_scan);
printf("fixed-point notation:%f\n",f_scan); 
printf("exponential notation:%e\n",f_scan);
printf("p notation:%a\n",f_scan);

return 0;
}

3.5

#include 
int main(void)
{ 
short ages;
float life_seconds;

printf("Please enter your ages:");
scanf("%d",&ages);
life_seconds=ages*3.156e7;
printf("%d years old means you have lived %f seconds\n",ages,life_seconds); 

return 0;
}

3.6

#include 
int main(void)
{ 
short water_weight;
float water_molecule;

printf("Please enter the water's weight in quart:");
scanf("%d",&water_weight);
water_molecule=water_weight*950/3.0e-23;
printf("%d quarts water contains %e molecules\n",water_weight,water_molecule); 

return 0;
}

3.7

#include 
int main(void)
{ 
float hight_inch;
float hight_cm;

printf("Please enter your hight in inch:");
scanf("%f",&hight_inch);
printf("%.2f inch means you're %.2f centimeters tall\n",hight_inch,hight_inch*2.54); 

return 0;
}

3.8

#include 
int main(void)
{ 
float cups;
float ounce;
float tablespoon;
float teaspoon ;

printf("Please enter the number of cups：");
scanf("%f",&cups);
ounce=cups*8.;
tablespoon=ounce*2.;
teaspoon=tablespoon*3.;
printf("%f cups means\n",cups); 
printf("%f ounce\n",ounce);
printf("%f tablespoon\n",tablespoon);
printf("%f teaspoon\n",teaspoon);

return 0;
}

第四章

4.1

#include 
int main(void)
{ 
char name[10],prename[10];

printf("Please enteryour name(such as Joseph Stalin):\n");
scanf("%s %s",name,prename);
printf("Now we know your name is %s,%s\n",name,prename);

return 0;
}

4.2

#include 
int main(void)
{ 
char name[20];
short x;

printf("Please enteryour name(such as Joseph Stalin):\n");
scanf("%s",name);
x=strlen(name)+3;
printf("\"%20s\"\n",name);
printf("\"%-20s\"\n",name);
printf("\"%*s\"\n",x,name);

return 0;
}

4.3

#include 
int main(void)
{ 
float a;
float b;

a=21.3;
b=21.290;
printf("The input is %.1f or %.1e\n",a,a);
printf("The input is %.3f or %.3e\n",b,b);

return 0;
}

4.4

#include 
int main(void)
{ 
float hight;
char name[10];

printf("please enter your name:\n");
scanf("%s",name);
printf("please enter your hight in centimeter:\n");
scanf("%f",&hight);
printf("%s,you are %.2f miters tall\n",name,hight/100);

return 0;
}

4.5

#include 
int main(void)
{ 
float speed;
float size;

printf("please enter your internet speed(in Mb/s):\n");
scanf("%f",&speed);
printf("please enter your file size(in MB):\n");
scanf("%f",&size);
printf("At %.2f megabites per second,a file of %.2f megabytes\n",speed,size);
printf("downloads in %.2f seconds\n",size/speed*8);

return 0;
}

4.6

#include 
int main(void)
{ 
int a,b;
char name[10],surname[10];

printf("please enter you name:\n");
scanf("%s",name);
printf("please enter you surname:\n");
scanf("%s",surname);
a=strlen(name);
b=strlen(surname);
printf("%s %s\n",name,surname);
printf("%*d %*d\n",a,a,b,b);
printf("%s %s\n",name,surname);
printf("%-*d %-*d\n",a,a,b,b);

return 0;
}

4.7

#include 
#include  
int main(void)
{ 
double a=1.0/3.0;
float b=1.0/3.0;
printf("double\n");
printf("%.6f\n",a);
printf("%.12f\n",a);
printf("%d\n",DBL_DIG);
printf("float\n");
printf("%.6f\n",b);
printf("%.12f\n",b);
printf("%d\n",FLT_DIG);
return 0;
}

4.8

#include 
#define turn1 3.785
int main(void)
{ 
const float turn2=1.609;
float distance;
float consume;
printf("请以英里为单位输入旅行的里程：\n");
scanf("%f",&distance);
printf("请以加仑为单位输入消耗的燃料：\n");
scanf("%f",&consume);
printf("所以旅行中的油耗是%.1f升/100公里",distance*turn2*100/consume/turn1);
return 0;
}

第五章

5.1

#include 
#define sec_per_min 60
#define min_per_hour 60;
int main(void)
{
    int minute;
    float hour;
    long second;
    printf("Please enter the minutes\n");
    scanf("%d",&minute);
    while(minute>0)
    {
        hour=(float)minute/min_per_hour;
        second=minute*sec_per_min;
        printf("%d minutes equal %d seconds or %f hours\n",
        minute,second,hour);
        scanf("%d",&minute);
    }
}

5.2

#include 
int main(void)
{
    int i=1;
    int num;
    int num_pre;

    printf("please enter a num:\n");
    scanf("%d",&num);
    num_pre=num;
    while(i++<12)
    {
        printf("%d ",num);
        num=num+1;
    }
    printf("\n");
    i=1;
    num=num_pre;
    while(i++<12)
    {
        printf("%d\t",num);
        num=num+1;
    }
    printf("\n");
    i=1;
    num=num_pre;
    while(i++<12)
    {
        printf("%d\n",num);
        num=num+1;
    }

    return 0;
}

5.3

#include 
#define days_per_week 7 
int main(void)
{
    int days;
    int day;
    int weeks;

    printf("please enter days:");
    scanf("%d",&days);
    weeks=days/days_per_week;
    day=days%days_per_week;
    printf("%d days are %d weeks,%d days.\n",days,weeks,day);

    return 0;
}

5.4

#include 
const float inch_per_cm=0.3937;
const float cm_per_feet=30.48;
int main(void)
{
    float height,height_1,inch;
    int feet;

    printf("enter a height in centimeters:");
    scanf("%f",&height);
    while(height>0)
    { 
    feet=height/cm_per_feet;
    height_1=height-feet*cm_per_feet;
    inch=height_1*inch_per_cm;
    printf("%.1f cm = %d feet,%.1f inches\n",height,feet,inch);
    printf("enter a height in centimeters (<=0 quit):");
    scanf("%f",&height);
    } 
    printf("bye\n");

    return 0;
}

5.5

#include 
int main(void)
{
    int count,sum;
    int days;

    printf("Please enter a num for sum:");
    scanf("%d",&days);
    count=0;
    sum=0;
    while(count++sum=sum+count;
    printf("sum=%d\n",sum);

    return 0;
}

5.6

#include 
int main(void)
{
    int count,sum;
    int days;

    printf("Please enter a num for sum:");
    scanf("%d",&days);
    count=0;
    sum=0;
    while(count++sum=sum+count*count;
    printf("sum=%d\n",sum);

    return 0;
}

5.7

#include 
float cube(float num);
int main(void)
{
    float num;

    printf("Please enter a number:");
    scanf("%f",&num);
    printf("The cube of this num is %f\n",cube(num));

    return 0; 
}
float cube(float num)
{
    return(num*num*num);
} 

5.8

#include 
int main(void)
{
    int num1,num2;

    printf("This program computes moduli.\n");
    printf("Enter an integer to serve as the second operand:");
    scanf("%d",&num1);
    printf("Now enter the first operand:");
    scanf("%d",&num2);
    while(num2>0)
    {
        printf("%d %% %d is %d\n",num2,num1,num2%num1);
        printf("Enter next number for first operand(<=0 to quit):");
        scanf("%d",&num2);
    }
    printf("Done\n");

    return 0;
} 

5.9

#include 
float Temperatures(float temp);
int main(void)
{
    float fah;
    int status; 

    printf("Please enter the Fahrenheit:");
    status=scanf("%f",&fah);
    while(status==1)
    {
        Temperatures(fah);
        printf("Please enter the Fahrenheit:(q to quit):");
        scanf("%f",&fah);
        status=scanf("%f",&fah);
    }

    return 0;
} 
float Temperatures(float temp)
{
    const float fah_need=32.0;
    const float kel_need=273.16;
    float kel,cent;

    cent=5.0/9.0*(temp-fah_need);
    kel=cent+kel_need;
    printf("digree centigrade is %f\n",cent);
    printf("digree kelvin is %f\n",kel);
}