当前课程知识点:C Programming > Chapter 4 Selection Structure > 4.3 Examples of Selection Structural Programs > 4.3 Examples of Selection Structural Programs.mp4
大家好
我是云南大学信息学院丁海燕老师
欢迎走进C语言程序设计课堂
今天我们讲解
选择结构程序举例
下面来看一个例子4.5
判断一个年份是否为闰年
问题描述
输入年份
判别该年是否为闰年
问题分析如下
年份year
为闰年的条件为
一
能够被4 整除
但不能被100 整除的年份
二
能够被400 整除的年份
只要满足任意一个
就可以确定它是闰年
算法流程图如下
输入年份year
判year满足条件1吗
是
leap=1
否则
进一步判断year满足条件2吗
如果满足条件二
leap=1
否则
leap=0
接下来
根据leap的值为1
输出是闰年
否则输出不是闰年
特点如下
一
使用多分支
二
使用标志变量leap
源程序如下
{ int year, leap ;
定义两个整型变量
提示输入一个年份
用 scanf语句
输入一个年份
if (year%4==0
&& year%100!=0)
则leap=1
否则
if (year%400==0)
leap=1
否则
leap=0
if (leap == 1)
输出
该年份是闰年
否则
输出该年份不是闰年
return 0
例如
输入2015
输出
2015
不是闰年
下面来看例4.6
求方程
ax2+bx+c=0的解
解题思路
处理以下各情况
一
a=0
不是二次方程
二
b2-4ac=0
有两个相等实根
三
b2-4ac>0
有两个不等实根
四
b2-4ac<0
有两个共轭复根
应当以p+qi
和p-qi的形式输出复数根
其中
p=-b/2a
q=( √b2-4ac)/2a
算法如下
输入以下程序
定义若干变量
输入a、b、c的值
若a==0
不是一元二次方程
否则
是一个一元二次方程
先计算disc
以减少重复计算
若disc为0
有两个相等的实根
否则
判断disc为正数还是负数
若disc>0
有两个不等的实根
x1,x2
输出x1,x2
否则
说明disc<0
有两个虚根
计算实部jp
计算虚部ip
输出两个虚根
编译
连接运行
输入1
逗号2
逗号1
输出方程有两个相等的实根
-1
输入1
2
2
输出方程有两个复数根
-1+i
-1-i
输入2
6
1
输出方程有两个不同的实根
-0.1771
和
-2.8229
我们来看案例4.7
运输公司对用户计算运输费用
路程越远
每吨·千米运费越低
标准如下
s < 250
没有折扣
250≤s < 500
2%的折扣
500≤s < 1000
5%的折扣
1000≤s < 2000
8%的折扣
2000≤s < 3000
10%的折扣
3000≤s
15%的折扣
解题思路为
设每吨每千米货物的基本运费为p
货物重为w
距离为s
折扣为d
则运费f的计算公式为
f=p×w×s×(1-d)
下面来看折扣的变化规律
折扣的“变化点”
都是250的倍数
在横轴上加一种坐标c
c的值为s/250
c代表250的倍数
当c<1时
表示s<250
无折扣
1≤c<2时
表示250≤s<500
折扣d=2%
2≤c<4时
d=5%
4≤c<8时
d=8%
8≤c<12时
d=10%
c≥12时
d=15%
程序如下
{ int c,s;定义两个整型变量
float p,w,d,f;
定义四个实型变量
scanf 输入单价
重量
距离
if
(s>=3000)
c=12
else
c=s/250
switch(c)
{ case 0:
d=0; break;
case 1: d=2; break;
case 2:
case 3:
d=5; break;
case 4:
case 5:
case 6:
case 7:
d=8; break;
case 8: case 9: case 10:
case 11: d=10; break;
case 12:
d=15; break;
f = p * w * s * (1 - d / 100);
输出f的值
return 0
输入单价
重量
折扣分别为100
20
300
输出运输费用为
588000.00元
好了
同学们
选择结构程序举例
我们就学到这儿
下节再见
-1.1 The development and characteristics of C language
--1.The development and characteristics of C language .mp4
--1.1 Self test questions
-1.2 A simple C Language program
--1.2 A simple C Language program.mp4
--【Source program】 Example 1.1 output a line of text Hello, world! "
--【Source program】 Example 1.2 program composed of multiple functions, find the larger of two integers
--1.2 Self test questions
-1.3 Program, Programming Language and C Program Running Steps
--1.3 Program, Programming Language and C Program Running Steps.mp4
--Running steps of C source program in CodeBlocks
--1.3 Self test questions
-chapter 1 Self-Test
-2.1 The Concept and Description of Algorithms
--2.1 The Concept and Description of Algorithms.mp4
--2.1 Self test questions
-2.2 Examples of Simple Algorithms, Computational Thinking and Structured Programming
--2.2 Examples of Simple Algorithms, Computational Thinking and Structured Programming.mp4
--2.2 Self test questions
-Chapter 2 Self test questions
-3.1 Simple Structure and Identifier of C Language Program
--3.1 Simple Structure and Identifier of C Language Program.mp4
--【Source program】 Example 3.1 input two integers and output the sum of two numbers.
--【Source program】 Example 3.2 input two integers and output the average value.
--【Source program】 Example 3.3 output the value of the character variable.
--3.1 Self test questions
-3.2 Constants, Variables and Assignments
--3.2 Constants, Variables and Assignments.mp4
--3.2 Self test questions
-3.3 Arithmetic, assignment, increment and decrement operators
--3.3 Arithmetic, assignment, increment and decrement operators.mp4
--3.3 Self test questions
-3.4 Conditions, commas, addresses, byte operators, and mixed operations among various numerical data
--3.4 Conditions, commas, addresses, byte operators, and mixed operations among various numerical data
--【Source program】 example of sizeof
--3.4 Self test questions
-3.5 Input and Output Examples and Character Input and Output
--3.5 Input and Output Examples and Character Input and Output.mp4
--【Source program】 Example. Find the root of quadratic equation of one variable.
--【Source program】 Example 1. Successively output three characters of BOY.
--【Source program】Example 2. Input 3 characters of BOY from the keyboard and output them to the screen
--3.5 Self test questions
-3.6 Formatted output printf function
--3.6 Formatted output printf function.mp4
--【Source program】 Example 3.4 output of integer data.
--【Source program】 Example 3.5 real data output.
--【Source program】 Example 3.6 character data output.
--【Source program】 Example 3.7 uses %s to output a string.
--3.6 Self test questions
-3.7 Formatted input scanf function
--3.7 Formatted input scanf function.mp4
--【Source program】 Example 3.8 Input and output integer data
--【Source program】Example 3.9 Input and output single precision and double precision real data.
--【Source program】Example 3.10 input and output character data.
--【Source program】Example 3.11 input and output string.
--3.7 Self test questions
-3.8 Basic Data Types of C Language
--3.8 Basic Data Types of C Language.mp4
--3.8 Self test questions
-Chapter 3 Self test questions
-Operator and expression self test questions
-4.1 Relational operators, logical operators, and if statements
--4.1 Relational operators, logical operators, and if statements.mp4
--【source example】Example 4.1 Find the root of the quadratic equation of one variable.
--【Source program】Example 4.2 Input two real numbers and output them from small to large.
--4.1 Self test questions
-4.2 Switch Statement
--【Source program】Example 4.3 uses switch statement to implement simple menu program
--【Source program】Example 4.4 converts centesimal score into the corresponding grade system score.
--4.2 Self test questions
-4.3 Examples of Selection Structural Programs
--4.3 Examples of Selection Structural Programs.mp4
--【Source program】 Example 4.5 determines whether a year is a leap year.
--【Source program】 Example 4.6 find the solution of quadratic equation of one variable.
--【Source program】Example 4.7 calculate the transportation cost for the user.
--4.3 Self test questions
-Chapter 4 Self test questions
-5.1 While and Do-While Statement
--5.1 While and Do…while statement.mp4
--【Source program】example 5.1 Use while statement to find 1 + 2 + 3 + +100
--【Source program】example 5.2 using do while statement to find 1 + 2 + 3 + +100
--5.1 Self test questions
-5.2 For Statement
--【Source program】example 5.3 Use for loop to find 1 + 2 + 3 +100
--5.2 Self test questions
-5.3 Change the State of Loop Execution and Nested Loop
--5.3 Change the state of loop execution and nested loop .mp4
--【Source program】example 5.4 collecting charity donations
--【Source program】example 5.5 output a number between 100 and 200 that cannot be divided by 3.
--【Source program】multiplication table
--【Source program】example 5.6 Output the following 4*5 matrix.
--5.3 Self test questions
-5.4 Loop Structure Program example 1
--5.4 Loop structure program example 1.mp4
--5.4 Self test questions
-5.5 Loop Structure Program example 2
--5.5 Loop structure program example 2.mp4
--【Source program】example 5. Output the following figure.
--【Source program】example6. The problem of 100 chickens and 100 coins
--【Source program】example 7. Find the approximate value of PI
--5.5 Self test questions
-Chapter 5 Self test questions
-6.1 Definition, Reference and Initialization of One-Dimensional Arrays
--6.1 Definition, Reference of One-Dimensional Arrays.mp4
--6.1 Self test questions
-6.2 One-Dimensional Array Programming
--6.2 One-Dimensional Array Programming.mp4
--【Source program】example 1. Fibonacci sequence
--【Source program】example 2. Find the maximum value and the minimum value.
--【Source program】example 3 exchanging array elements in reverse order.
--【Source program】example 4. Bubble sorting.
--6.2 Self test questions
-6.3 Definition, Reference and Initialization of Two-Dimensional Arrays
--6.3 Definition, Reference of Two-Dimensional Arrays.mp4
--6.3 Self test questions
-6.4 Two-Dimensional Array Programming
--6.4 Two-Dimensional Array Programming.mp4
--【Source program】example 1. Get the average score of each subject.
--【Source program】Example 2. The elements of row and column of a 2D array are interchanged
--6.4 Self test questions
-6.5 Definition, initialization and input and output of character arrays
--6.5 Definition, initialization and input and output of character arrays .mp4
--【Source program】Example 6.6 Output a known string.
--【Source program】Example 6.7 Output a diamond.
--【Source program】Example 6.10 Sorting of strings.
--6.5 Self test questions
-6.6 String Processing Function
--6.6 String Processing Function.mp4
--6.6 Self test questions
-6.7 Character Array Programming
--6.7 Character Array Programming.mp4
--6.7 Self test questions
-Chapter 6 Self test questions
-7.1 Function Concept and How to Define and Call Functions
--7.1 Function Concept and How to Define and Call Functions.mp4
--7.1 Self test questions
-7.2 Data Transfer in Function Call, Call Procedure and Function Return Value
--7.2 Data Transfer in Function Call, Call Procedure and Function Return Value.mp4
--7.2 Self test questions
-7.3 Declarations of called functions and nested calls to functions
--7.3 Declarations of called functions and nested calls to functions .mp4
--【Source program】Example 7.4 use a function to find the sum of t
--7.3 Self test questions
-7.4 Recursive call to function
--7.4 Recursive call to function.mp4
--【Source program】Example 7.6. How old is the fifth student?
--【Source program】Example 7.7 Use recursion method to find n!
--7.4 Self test questions
-7.5 Array as function parameter (1)
--7.5 Array as function parameter (1).mp4
--【Source program】Example 7.10
--7.5 Self test questions
-7.6 Array as function parameter (2)
--7.6 Array as function parameter (2).mp4
--【Source program】Selection sorting.
--【Source program】Example 7.13 find the maximum of a 3×4 matrix.
--7.6 Self test questions
-7.7 Local and global variables, internal and external functions
--7.7 Local and global variables, internal and external functions.mp4
--【Source program】Example 7.14
--7.7 Self test questions
-7.8 The Survival Period of Variables and the Storage Mode of Local Variables
--7.8 The Survival Period of Variables and the Storage Mode of Local Variables.mp4
--【Source program】Example 7.17
--7.8 Self test questions
-7.9 Storage Categories of Global Variables
--7.9 Storage Categories of Global Variables.mp4
--7.9 Self test questions
-Chapter 7 Self test questions
-8.1 Pointer Concept, Definition and Reference of Pointer Variables
--8.1 Pointer Concept, Definition and Reference of Pointer Variables.mp4
--8.1 Self test questions
-8.2 Pointer variables as function parameters
--8.2 Pointer variables as function parameters.mp4
--【Source program】Example 8.3. Exchange two data with function call.
--8.2 Self test questions
-8.3 Pointer of array element, operation of pointer and reference of array element by pointer
--8.3 Pointer of array element, operation of pointer and reference of array element by pointer.mp4
--【Source program】Point to array elements with pointer variables.
--8.3 Self test questions
-8.4 Using Array Name as Function Parameter
--8.4 Using Array Name as Function Parameter.mp4
--【Source program】Store array elements in reverse order.
--8.4 Self test questions
-8.5 Reference to multidimensional arrays by pointers
--8.5 Reference to multidimensional arrays by pointers.mp4
--【Source program】Pointer variable pointing to one-dimensional array.
--8.5 Self test questions
-8.6 Referencing strings through pointers
--8.6 Referencing strings through pointers.mp4
--【Source program】Reference string by pointer.
--8.6 Self test questions
-8.7 Character pointer as function parameter
--8.7 Character pointer as function parameter.mp4
--【Source program】Character pointer as function parameter.
--8.7 Self test questions
-8.8 Pointer pointing to function
--8.8 Pointer pointing to function.mp4
--【Source program】Pointer variable pointing to the function.
--8.8 Self test questions
-8.9 Functions that return pointer values
--8.9 Functions that return pointer values.mp4
--【Source program】Intercept substring.
--8.9 Self test questions
-8.10 Pointer arrays and multiple pointers
--8.10 Pointer arrays and multiple pointers.mp4
--【Source program】Sorting of strings.
--8.10 Self test questions
-8.11 Dynamic memory allocation and pointer variables pointing to it
--8.11 Dynamic memory allocation and pointer variables pointing to it.mp4
--【Source program】Dynamic memory allocation.
--8.11 Self test questions
-Chapter 8 Self test questions
-9.1 Define and use structural variables
--9.1 Define and use structural variables.mp4
--【Source program】Structure variable
--9.1 Self test questions
-9.2 Using structure arrays
--9.2 Using structure arrays.mp4
--【Source program】Structure array
--9.2 Self test questions
-9.3 Structure pointer
--【Source program】Structure pointer
--9.3 Self test questions
-Chapter 9 Self test questions
-CodeBlocks Baidu online disk download address
-Final Exam
--final exam