習題3.1
編寫一個程序逾苫，首先給用戶以下兩種選擇：
（1）將溫度從攝氏度轉(zhuǎn)換為華氏度。
（2）將溫度從華氏度轉(zhuǎn)化為攝氏度枚钓。
接著铅搓，程序提示用戶輸入溫度值，并輸出轉(zhuǎn)換后的數(shù)值搀捷。
Paste_Image.png
方法一：
# include <stdio.h>
int main (void)
{
float Fahrenheit_temperate = 0;
float Celsius_temperate =0;
float temperate = 0;
printf(" Enter the number of temperater: ");
scanf("%.2f", &temperater);
Fahrenheit_temperate = temperater*1.8+32
Celsius_temperate = (temperater-32)*5%9
printf("%.f 攝氏度= %.f華氏度：",temperater,Fahrenheit_temperate);
scanf("%.2f", &temperater);
printf("%.f華氏度=%.f攝氏度： ", temperater,Celsius_temperate);
scanf("%.2f",&temperater);
return 0;
}
方法二：
#include <stdio.h>
int main()
{
float temperature_F = 0; //華氏度
float temperature_C = 0; //攝氏度
printf("請輸入溫度值: \n");
scanf("%f",&temperature_C);
temperature_F = temperature_C *1.8 + 32;
temperature_C = (temperature_F - 32)/1.8;
printf("%.2f\n", temperature_F);
printf("%.2f\n",temperature_C);
return 0;
}
習題 3.3
編寫一個程序狸吞，根據(jù)從鍵盤輸入的一個數(shù)值，計算總價（單價是$5）,數(shù)值超過30的折扣是10%指煎， 數(shù)值超過50的折扣是15%。
- 使用多項選擇結(jié)構(gòu) else-if
#include <stdio.h>
int main(void)
{
const int unit_price = 5;
int quantity = 0;
float total_price = 0;
float discont = 0;
printf("Enter the number of quantity: ");
scanf("%d",&quantity);
if(quantity <=30)
{
printf("The total of price is %.2f\n",quantity*unit_price);
scanf("%.2f",&total_price);
}
else if(quantity> 30)
{
printf("The total of price is %.2f\n", quantity*unit_price*0.9);
scanf("%.2f",&total_price);
}
else (quantity >50)
{
printf("The total of price is %.2f\n",quantity*unit_price*0.85);
scanf("%.2f",&total_price);
}
return 0;
}
- 使用條件運算符
在你不知道為什么的時候便斥，不要把過的時間放在為什么上至壤，去想辦法解決問題，先記住是什么枢纠，再問為什么 有時候不需要問為什么像街，規(guī)范就是這樣的，你只需要記住是什么就好了
#include <stdio.h>
int main(void)
{
const int unit_price = 5;
const double discount1 = 0.1;
const double discount2 = 0.15
double total price = 0.0;
int quantity = 0;
printf("Enter the number that you want to buy: ");
scanf(" %d", &quantity);
total_price = quantity*unit_price*(1.0 -
(quantity > 50 ? discount2 : (
( quantity > 30 ?discount1: ))));
printf("The price for %d is $%.2f\n", quantity, total_price);
return 0;
}
習題3.2 編寫一個程序晋渺，提示用戶輸入3個整數(shù)值镰绎，分別代表月，日木西，年畴栖。例如用戶輸入了12、31八千、2003吗讶，程序就以31stDecember 2003的格式輸出該日期燎猛。
必須在日期值得后面加上th 、nd照皆、st和rd,例如1st重绷、2nd、3rd膜毁、4th昭卓、11th、12th瘟滨、13th候醒、14th、21st室奏、22nd火焰、23rd、24th
當時學的時候你不懂胧沫，你記下來昌简，但是你有時間回頭再來看看嗎？
人家說對于初學者而言绒怨，C語言入門經(jīng)典這本書對于初學者并不簡單纯赎，但是回頭再看這些書的時候，你會有不一樣的領(lǐng)悟南蹂，所以我浪費時間把它記錄下來犬金，希望我不是真的浪費時間吧！
#include "stdafx.h"
#include <stdio.h>
int _tmain(int argc, _TCHAR* argv[])
{
int year = 0;
int month = 0;
int day = 0;
printf_s("please enter the year：");
scanf_s("%d", &year);
printf_s("please enter the month：");
scanf_s("%d", &month);
printf_s("please enter the day：");
scanf_s("%d", &day);
switch (day) {
case 1:
case 21:
case 31:
printf_s("%dst ", day);
break;
case 2:
case 22:
printf_s("%dnd ", day);
break;
case 3:
case 23:
printf_s("%drd ", day);
break;
default:
printf_s("%dth ", day);
break;
}
switch (month) {
case 1:
printf_s("January ");
break;
case 2:
printf_s("February ");
break;
case 3:
printf_s("March ");
break;
case 4:
printf_s("April ");
break;
case 5:
printf_s("May ");
break;
case 6:
printf_s("June ");
break;
case 7:
printf_s("July ");
break;
case 8:
printf_s("August ");
break;
case 9:
printf_s("September ");
break;
case 10:
printf_s("October ");
break;
case 11:
printf_s("November ");
break;
case 12:
printf_s("December ");
break;
default:
break;
}
printf_s("%d\n", year);
return 0;
}
#include<stdio.h>
int main(void)
{
int month = 0;
int day = 0;
int year = 0;
printf("please enter the number of integer: ");//提示用戶輸入三個整數(shù)
scanf_s("%d %d %d", &month, &day, &year);//讀取三個整數(shù)
switch (day)
{
case 1:
case 21:
printf("%dst",day);
break;
case 2:
case 22:
printf("%dnd",day);
break;
case 3:
case 23:
printf("%drd",day);
break;
case 4:
case 11:
case 12:
case 13:
case 14:
case 24:
printf("%dth",day);
break;
default:
break;
}
switch (month)
{
case 1:
printf("January");
break;
case 2:
printf("Feburday");
break;
case 3:
printf("March");
break;
case 4:
printf("May");
break;
case 5:
printf("June");
break;
case 6:
printf("July");
break;
case 7:
printf("August");
break;
case 9:
printf("September");
break;
case 10:
printf("October");
break;
case 11:
printf("November");
break;
case 12:
printf("December");
break;
default:
break;
}
printf("%d", year);
return 0;
```
```
#include <stdio.h>
int main()
{
int year = 0;
int month = 0;
int day = 0;
printf("請輸入日期 :\n");
scanf("%d六剥、%d晚顷、%d",&month,&day,&year);
switch(month)
{
case 1:
printf("January");
break;
case 2:
printf("February");
break;
case 3:
printf("March");
break;
case 4:
printf("April");
break;
case 5:
printf("May");
break;
case 6:
printf("June");
break;
case 7:
printf("July");
break;
case 8:
printf("August");
break;
case 9:
printf("September");
break;
case 10:
printf("October");
break;
case 11:
printf("November");
break;
case 12:
printf("December");
break;
default:
break;
}
switch(day)
{
case 1:
case 21:
case 31:
printf("%dnd",day);
break;
case 22:
case 2:
printf("%dnd",day);
break;
case 3:
case 23:
printf("%drd",day);
break;
default:
printf("%dth",day);
break;
}
printf("%d\n",year);
return 0;
}
```