C primer plus第5章（运算符、表达式和语句）习题

3.

#include <stdio.h>int main (void){    int i = 1;    float n;    printf("Watch out! Here come a bunch of fractions!\n");    while(i++ < 30) {        n = 1.0/i;//将1改为1.0，当2个数都是整数时，第一次结果为1，当I增大时结果会一直为0，改为1.0（浮点型）则会有不同结果        printf("%f\n",n);    }    printf("That`s all,folks!\r");    return 0;}

4.

#include <stdio.h>#define FORMAT "%s! C is cool!\n"int main (void){    int num = 10;    printf(FORMAT, FORMAT);    printf("%d\n", ++num);    printf("%d\n", num++);    printf("%d\n", num--);    printf("%d\n", num);    return 0;}

结果

%s! C is cool!
! C is cool!
11
11
12
11

6.

#include <stdio.h>int main (void){    char c1,c2;    int diff;    float num;    c1 = 'S';    c2 = 'O';    diff = c1 - c2;    num = diff;    printf("%c%c%c: %d %3.2f\n", c1, c2,c1,diff,num);    return 0;}

打印结果

SOS: 4 4.00

7.

#include <stdio.h>#define TEN 10int main (void){    int n = 0;    while(n++ < TEN)        printf("%5d",n);    printf("\n");    return 0;}

8.

#include <stdio.h>int main (void){    char c = 'a';    while(c <= 'g')        printf("%5c",c++);    printf("\n");    return 0;}

9.

a.

   1   2 

b.

   101

   102

   103

   103

c.

stuvw

编程练习

1.

#include <stdio.h>int main (void){    const int MAX = 60;    int num;    while(num > 0) {        scanf("%d",&num);    }    return 0;}

2.

#include <stdio.h>int main (void){    int pl = 10;    int num;    printf("请输入数字\n");    scanf("%d",&num);    while(pl >= 0) {        printf("%d\n",num+pl);        pl--;    }    return 0;}

3.

#include <stdio.h>int main (void){    const int PW = 7;    int days;    printf("请输入天数\n");    scanf("%d",&days);    printf("%d周%d天",days/PW,days%PW);    return 0;}

4.

#include <stdio.h>int main (void){    const float I_T_M = 2.54;    const float M_T_I = 0.3937;    float cm;    while(cm > 0) {        printf("请输入厘米长度\n");        scanf("%f",&cm);        printf("%.2fcm\n%.2finch\n",cm,cm*I_T_M);    }    return 0;}

5.

#include <stdio.h>int main (void){    int count,sum,days;    count = 0;    sum = 0;    scanf("%d",&days);    while(count++ < days)        sum = sum + count;    printf("sum = %d\n", sum);    return 0;}

6.

#include <stdio.h>int main (void){    int count,sum,days;    count = 0;    sum = 0;    scanf("%d",&days);    while(count++ < days)        sum = sum + count * count;    printf("sum = %d\n", sum);    return 0;}

7.

#include <stdio.h>int main (void){    float num;    scanf("%f",&num);    printf("%f", num * num * num);    return 0;}

8.

#include <stdio.h>//用到atof函数需要此包#include <stdlib.h>int main (void){    char fahrenheit[40];    double params;    int n;    while(1)    {        printf("请输入华氏温度\n");        scanf("%s",fahrenheit);        n = strlen(fahrenheit);        int i = 0;        for(i=0; i<n; i++)        {            if((fahrenheit[i] < '0' || fahrenheit[i] > '9') && fahrenheit[i] != '.')            {                return 0;            }        }        temperatures(atof(fahrenheit));    }    return 0;}void temperatures(double fahrenheit){    const float C1 = 1.8;    const float C2 = 32.0;    const float K = 273.16;    double celsius,kelvin;    celsius = C1 * fahrenheit + C2;    kelvin = celsius * K;    printf("摄氏%f度\n",celsius);    printf("绝对温度%f度\n",kelvin);}