7.16 程式設計練習
- 編寫一個程式讀取輸入，讀到#字元停止，然後報告讀取的空格數、換行數和其他所有字元的數量。
#include <stdio.h>
int main()
{
int num_n = 0;
int num_space = 0;
int num_else = 0;
char ch;
while (scanf("%c", &ch) == 1)
{
if (ch == '#')
break;
else if (ch == ' ')
num_space++;
else if (ch == '\n')
num_n++;
else
num_else++;
}
printf("num_n:%3d\num_else:%3d\nnum_space:%3d\n", \
num_n, num_else, num_space);
return 0;
}
- 編寫一個程式讀取輸入，讀到#字元停止。程式要列印每個輸入的字元以及對應的ASCII碼（十進制）。一行列印8個字元。建議:使用字元計數和求模運算符（%）在每8個循環周期時列印一個換行符。
#include <stdio.h>
#define SIZE 8
int main()
{
char ch;
int num = 1;
while (scanf("%c", &ch) == 1)
{
if (ch == '#')
{
break;
}
else
{
if (num % SIZE == 0)
printf("%-5d\n",ch);
else
printf("%-5d",ch);
num++;
}
}
return 0;
}
-
編寫一個程式，讀取整數直到使用者輸入 0。
輸入結束後，程式應報告使用者輸入的偶數（不包括 0）個數、
這些偶數的平均值、輸入的奇數個數及其奇數的平均值
#include <stdio.h>
int main()
{
int num_even = 0;
int num_odd = 0;
int sum_even =0;
int sum_odd = 0;
int num;
while (scanf("%d", &num) == 1)
{
if (num == 0)
{
break;
}
else if (num % 2 == 0)
{
num_even++;
sum_even +=num;
}
else
{
num_odd++;
sum_odd +=num;
}
}
printf("num_even:%-5d,num_odd:%-5d\n", num_even, num_odd);
printf("sum_even:%-5d,sum_odd:%-5d\n", sum_even, sum_odd);
printf("ave_even:%-5d,ave_odd:%-5d\n",sum_even / num_even, \
sum_odd / num_odd);
return 0;
}
- 使用if else語句編寫一個程式讀取輸入，讀到#停止。用感歎号代替句号，用兩個感歎号代替原來的感歎号，最後報告進行了多少次替代。
#include <stdio.h>
int main()
{
int i = 0, j = 0;
char ch;
while ((ch = getchar()) != '#')
{
if (ch == '.')
{
putchar('!');
i++;
}
else if (ch == '!')
{
putchar('!');
putchar('!');
j++;
}
else
{
putchar(ch);
}
}
printf("\nthe times of '.', replaced:\n:%-5d\n", i);
printf("the times of '!' replaced:\n%-5d\n", j);
return 0;
}
- 用switch重寫練習4。
#include <stdio.h>
int main()
{
int i = 0, j = 0;
char ch;
while ((ch = getchar()) != '#')
{
switch (ch)
{
case '.':
{
putchar('!');
i++;
break;
}
case '!':
{
putchar('!');
putchar('!');
break;
j++;
}
default:
{
putchar(ch);
}
}
}
printf("\nthe times of '.', replaced:\n:%-5d\n", i);
printf("the times of '!' replaced:\n%-5d\n", j);
return 0;
}
- 編寫程式輸入，讀到#停止，報告ei出現的次數。
#include <stdio.h>
int main()
{
int count = 0;
char ch, ch_last;
while ((ch = getchar()) != '\n')
{
if (ch == 'i' && ch_last == 'e')
{
count++;
ch_last = ch;
}
else
{
ch_last = ch;
}
}
printf("\nthe times of occurrences of 'ei' is:%-2d\n",count);
return 0;
}
-
編寫一個程式，提示使用者輸入一周工作的小時數，然後列印工資總額、稅金和淨收入 做如下假設：
a.基本工資 = 1000美元 / 小時
b.加班(超過40小時) = 1.5倍時間
c.稅率: 前300美元為15% 續150美元為20% 餘下的為25%
用#define定義符号常量，不用在意是否符合目前的稅法
#include<stdio.h>
#define TIME_LIMIT 40
#define PAY_HOUR 10
int main()
{
float workhours, pre_tax, after_tax;
printf("please enter your working hours:");
while(scanf("%f", &workhours) == 1)
{
if (workhours <= TIME_LIMIT)
{
pre_tax = PAY_HOUR * workhours;
}
else
{
pre_tax = PAY_HOUR * (TIME_LIMIT + (workhours - TIME_LIMIT) * 1.5);
}
if (pre_tax <=300)
{
after_tax = pre_tax - pre_tax * 0.15;
}
else if (pre_tax > 300 && pre_tax <=450)
{
after_tax = pre_tax - 300 * 0.15 - (pre_tax - 300) * 0.2;
}
else
{
after_tax = pre_tax - 300 * 0.15 - 150 * 0.2 - (pre_tax - 450) * 0.25;
}
printf("your salary before tax is:%-5.2f\n", pre_tax);
printf("your salary after tax is:%-5.2f\n", after_tax);
printf("please enter your working hours again or enter 'q' to quit:");
}
return 0;
}
-
修改練習7的假設a,讓程式可以給出一個供選擇的工資等級菜單
使用 switch 完成工資等級的選擇。
運作程式後，顯示的菜單應該類似這樣：
*******************************************************************************
Enter the number corresponding to the desired pay rate of action:
1) $8.75/hr 2) $9.33/hr
3) $10.00/hr 4) $11.20/hr
5) quit
*******************************************************************************
如果選擇一個1~4其中的一個數字，程式應該詢問使用者工作的小時數。
程式要通過循環運作，除非使用者輸入 5。
如果輸入1~5 以外的數字，程式應該提醒使用者輸入正确的選項，
然後再重複顯示菜單提示使用者輸入。
使用#define建立符号常量表示各工資等級和稅率
#include<stdio.h>
#define TIME_LIMIT 40
int main()
{
int i, pay_level;
float workhours, pre_tax, after_tax, pay_hour;
for (i = 1; i <= 65; i++)
putchar('*');
printf("\nEnter the number corresponding to the desired pay rate or action:\n");
printf("%d) $8.75/hr%-20d) $9.33/hr\n%d) $10.00/hr%-20d) $11.20/hr\n%d) quit)\n", 1, 2, 3, 4, 5);
for (i = 1; i <= 65; i++)
putchar('*');
printf("\n");
while(scanf("%d", &pay_level) == 1)
{
if (pay_level >=0 && pay_level <=4)
{
printf("Enter your working hours:");
scanf("%f", &workhours);
switch (pay_level)
{
case 1:
{
pay_hour = 8.75;
break;
}
case 2:
{
pay_hour = 9.33;
break;
}
case 3:
{
pay_hour = 10.00;
break;
}
case 4:
{
pay_hour = 11.20;
break;
}
default:
/*do nothing*/;
}
}
else if (pay_level == 5)
{
break;
}
else
{
printf("Enter the correct number, only 1-5 is availble:\n");
}
if (workhours <= TIME_LIMIT)
{
pre_tax = pay_hour * workhours;
}
else
{
pre_tax = pay_hour * (TIME_LIMIT + (workhours - TIME_LIMIT) * 1.5);
}
if (pre_tax <=300)
{
after_tax = pre_tax - pre_tax * 0.15;
}
else if (pre_tax > 300 && pre_tax <=450)
{
after_tax = pre_tax - 300 * 0.15 - (pre_tax - 300) * 0.2;
}
else
{
after_tax = pre_tax - 300 * 0.15 - 150 * 0.2 - (pre_tax - 450) * 0.25;
}
printf("your salary before tax is:%-5.2f\n", pre_tax);
printf("your salary after tax is:%-5.2f\n", after_tax);
printf("please enter the number again or enter 5 to quit:");
}
return 0;
}
- 編寫一個程式，隻接受正整數輸入，然後顯示所有小于等于該數的素數。
#include<stdio.h>
int main()
{
int i, j, counter, num;
printf("please enter the integer:");
scanf("%d", &num);
while (num > 0)
{
for (i = 1; i <= num; i++)
{
for (j = 1, counter = 0; j <= i; j++)
{
if (i % j == 0)
{
counter++;
if (counter > 2)
{
break;
}
else
{
/*do nothing*/
}
}
else
{
/*do nothing*/
}
}
if (counter == 2)
{
printf("%-5d\n", i);
}
else
{
/*do nothing*/
}
}
break;
}
return 0;
}
-
1988年的美國聯邦稅收計劃是近代最簡單的稅收方案。它分為4個類别，每個類别有兩個等級。下面是稅收計劃的摘要(美元數為應征稅的收入)：
類别 稅金
單身------------------------17850美元按15%計，超出部分按28%計
戶主------------------------23900美元按15%計，超出部分按28%計
已婚，共有---------------29750美元按15%計，超出部分按28%計
已婚，離異---------------14875美元按15%計，超出部分按28%計
例如：一位工資為20000美元的單身納稅人，應繳納稅費 0.15x17850+0.28x(20000-17850)美元。編寫一個程式，讓使用者指定繳納稅金的種類和應納稅收入，然後計算稅金。程式應通過循環讓使用者可以多次輸入。
#include<stdio.h>
#define RATE1 0.15
#define RATE2 0.28
#define LEVEL1 17850
#define LEVEL2 23900
#define LEVEL3 29750
#define LEVEL4 14875
int main()
{
int category;
float pre_tax, after_tax, tax_limit;
printf("%d)單身%23d)戶主\n%d)已婚、共有%17d已婚、離異\nplease enter the number corresponding your category correctly as above:", 1, 2, 3, 4);
while (scanf("%d", &category) == 1)
{
if (category >= 1 && category <= 4)
{
switch (category)
{
case 1:
{
tax_limit = LEVEL1;
break;
}
case 2:
{
tax_limit = LEVEL2;
break;
}
case 3:
{
tax_limit = LEVEL3;
break;
}
case 4:
{
tax_limit = LEVEL4;
break;
}
}
}
else
{
printf("the number is error, enter 'q' to quit or enter number again:");
continue;
}
printf("please enter your salary:");
scanf("%f", &pre_tax);
if (pre_tax <= tax_limit)
{
after_tax = pre_tax * (1 - RATE1);
}
else
{
after_tax = pre_tax - tax_limit *RATE1 - (pre_tax - tax_limit) * RATE2;
}
printf("tax_limit:%-5.2f\nsalary before tax:%-5.2f\nsalary after tax:%-5.2f\n", tax_limit, pre_tax, after_tax);
printf("please continue to enter the number corresponding your category:");
}
printf("your input is not a number, THX!");
return 0;
}
- ABC郵政雜貨店出售的洋薊售價為2.05美元/磅，甜菜售價為1.15美元/磅，胡蘿蔔售價為1.09美元/磅。添加運費之前，100美元的訂單有5%的打折優惠。少于或等于5磅的訂單收取6.5美元的運費和包裝費，5磅~20磅的訂單收取14美元的運費和包裝費，超過20磅的訂單在14美元的基礎上每續重1磅增加0.5美元。編寫一個程式，在循環中用switch語句實作使用者輸入不同的字母時有不同的響應，即輸入a響應是讓使用者輸入洋薊的磅數，b是甜菜的磅數，c是胡蘿蔔的磅數，q退出訂購。程式要記錄累計的重量。然後，該程式要計算貨物總價、折扣（如果有的話）、運費和包裝費。随後，程式要顯示所有的購買資訊：物品售價、訂購的重量（磅）、訂購的蔬菜費用、訂單的總費用、折扣（如果有的話）、運費和包裝費、以及所有的費用總額。
#include<stdio.h>
#define ARTICHOKE 2.05
#define BEET 1.15
#define CARROT 1.09
#define DISCOUNT 0.05
#define LEVEL1 6.5
#define LEVEL2 14
#define RATE 0.5
int main()
{
char name_veg;
float weight, price_unit, price_total, pay, freight;
printf("%7d)a means artichoke\n%7d)b means beet\n%7d)c means carrot\n%7d)q means quit\n", 1, 2, 3, 4);
printf("Please enter initials of the vegetable name you want to buy:");
while (scanf("%c", &name_veg) == 1)
{
switch (name_veg)
{
case 'a':
{
price_unit = ARTICHOKE;
break;
}
case 'b':
{
price_unit = BEET;
break;
}
case 'c':
{
price_unit = CARROT;
break;
}
case 'q':
{
break;
}
}
printf("enter how many pounds you need:");
scanf("%f", &weight);
price_total = price_unit * weight;
if (price_total >= 100)
{
pay = price_total * (1 - DISCOUNT);
}
else
{
pay = price_total;
}
if (weight <= 5)
{
freight = LEVEL1;
}
else if (weight >5 && weight <=20)
{
freight = LEVEL2;
}
else
{
freight = LEVEL2 + (weight - 20) * RATE;
}
printf("the money you should pay is:%-5.2f", pay + freight);
break;
}
return 0;
}
![C Primer Plus 第4章 字元串和格式化輸入/輸出[圖]](data:image/gif;base64,R0lGODlhAQABAIAAAP///wAAACwAAAAAAQABAAACAkQBADs=)