当前课程知识点：C Programming > Chapter 6 Batch Data Processing with Array > 6.5 Definition, initialization and input and output of character arrays > 6.5 Definition, initialization and input and output of character arrays .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
今天我们讲解字符数组的定义、初始化和输入输出
字符型数据是以字符的ASCII代码存储在存储单元中的
一般占一个字节。C语言中没有字符串类型
字符串是存放在字符型数组中的
下面介绍怎样定义字符数组
• 用来存放字符数据的数组是字符数组
• 字符数组中的一个元素存放一个字符
• 定义字符数组的方法与定义数值型数组的方法类似
由于字符数据是以整数形式（ASCII代码）存放的
因此也可以用整型数组来存放字符数据
例如
char c[10];
从c[0]到c[9]可以赋值一个字符
字符串为I am happy
定义字符数组的同时给数组元素赋值
称为字符数组的初始化
例如char c[10]赋值为{单一}的字符
把10个字符依次分别赋给c[0]到c[9]这10个元素
数组状态如图1所示。
如果在定义字符数组时不进行初始化
则数组中各元素的值是不可预料的
如果花括号中提供的初值个数（即字符个数）
大于数组长度，则出现语法错误
如果初值个数小于数组长度
则只将这些字符赋给数组中前面那些元素
其余的元素自动设为空字符（即’\0’）。
例如char c[10]赋值以下字符
数组状态如图2所示。
也可以定义和初始化一个二维字符数组
例如定义char diamond[5][5]
初始化如下
可以引用字符数组中的一个元素，得到一个字符
例6.6 输出一个已知的字符串
解题思路：
–定义一个字符数组，并用“初始化列表”对其赋以初值
–用循环逐个输出此字符数组中的字符
源程序如下
{ char c[15]并赋初值
int i;
for(i=0;i<15;i++)
printf("%c",c[i]);
printf(" ");
}完
程序输出I am a student.
下面来看例6.7 输出一个菱形图
解题思路：
–定义一个字符型的二维数组，用“初始化列表”进行初始化
–用嵌套的for循环输出字符数组中的所有元素
程序如下：运行显示一个菱形
{char diamond[][5]={{' ',' ','*'},{' ','*',' ','*'}
进行初始化
int i,j;
for (i=0;i<5;i++)
{for (j=0;j<5;j++)
printf("%c",diamond[i][j]);
printf(" ");}
C系统在用字符数组存储字符串常量时
会自动加入一个’\0’作为结束符。
•在C语言中，是将字符串作为字符数组来处理的
•关心的是字符串的有效长度而不是字符数组的长度
•为了测定字符串的实际长度
•C语言规定了字符串结束标志’\0’
•’\0’代表ASCII码为0的字符
•从ASCII码表可以查到，ASCII码为0的字符
•不是一个可以显示的字符，而是一个“空操作符”
即它什么也不做
•用它作为字符串结束标志不会产生附加的
操作或增加有效字符，只起一个供辨别的标志
例如char c[]={”I am happy”}; 可写成
char c[]=”I am happy”;
相当于char c[11]={”I am happy”};
char c[10]={”China”}; 可写成
char c[10]=”China”;
从c[5]开始，元素值均为\0
printf(”%s”,c); 只显示China
下面介绍字符数组的输入输出
•字符数组的输入输出可以有两种方法：
– 逐个字符输入输出（%c）
– 整个字符串一次输入输出（%s）
•输出的字符中不包括结束符’\0’
•用%s输出字符串时，printf函数中的输出项
•是字符数组名，不是数组元素名
•如果一个字符数组中包含多个’\0’
•则遇第一个’\0’时输出就结束
•可以用scanf函数输入一个字符串
•scanf函数中的输入项c是已定义的字符数组名
•输入的字符串应短于已定义的字符数组的长度
例如，已定义：
char c[6];
scanf(”%s”,c);
从键盘输入 China↙回车
系统自动在China后面加一个’\0’结束符。
如果利用一个scanf函数输入多个字符串
则应在输入时以空格分隔。例如，
char str1[5],str2[5],str3[5];
scanf(“%s%s%s”,str1,str2,str3);
输入How are you? ↙回车
系统把空格字符作为输入的字符串之间的分隔符
把 How are you?看作3个字符串输入
在输入完后，str1存储的字符串是How
str2存储的字符串是are, str3存储的字符串是you
数组中未被赋值的元素的值自动置’\0’。如图所示
注意：
scanf 函数中的输入项如果是字符数组名
不要再加地址符 &
因为在C语言中数组名代表该数组的起始地址
char str[13];
scanf(“%s”,&str) 是错误的
好了，同学们，字符数组的定义、初始化和输入输出
我们就学习到这儿，下节课再见！
-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
