C语言程序实例

1、数组的引用:#in clude<stdio.h>void main (int argc,char *argv) int x5 = 2,3,1,4,6 ;int i;for (i = 0; i < 5; i+)printf("%dn", 2 * xi);一维数组的遍历:#in clude<stdio.h>void main (i nt argc, char *argv)int x5 = 1,2,3,4,5 ;int i = 0;for (i = 0; i < 5; i+)prin tf("x%d:%dn", i, xi)

2、;一维数组的最值:#include <stdio.h>int main( int argc, char * argv ) int x5 = 1,2,3,4,5 ;int nMax = x0;int i = 0;for (i = 1; i < 5; i+)if (xi > nMax)printf( "max:%dn", nMax);return 0;一维数组排序：#include <stdio.h>void main( int argc, char * argv ) int arr5 = 9, 8, 3, 5, 2 ;int temp =

3、0;int i, j;printf（"冒泡排序前：n"）;for (i = 0; i< 5; i+)printf( "%d ", arri);printf( " n");for (i = 0; i < 5-1; i+)for (j = 0; j < 5 - 1 - i; j+)if (arrj > arrj + 1) temp = arrj;arrj = arrj + 1;arrj + 1 = temp;pri ntf("冒泡排序后：n"）;for (i =0; i < 5; i+)p

4、ri ntf("%d " , arri);printf( "n");二维数组的遍历#include <stdio.h>void main()/声明并初始化数组int array34 = 1,2,3,4,5,6,7,8,9,10,11,12 ;for ( int i = 0; i < 3; i+)/ 循环遍历行for ( int j = 0; j < 4; j+)/ 循环遍历列printf( "n" ); /每一行的末尾添加换行符二维数组应用#i nclude <stdio.h>void main(

5、int argc, char * argv ) int StuScore53 = /张同学88,70,90,/王同学80,80,60,/李同学89,60,85,/赵同学80,75,78,/周同学70,80,80,；int m = 0, n = 0;int nStuTotalScore;int nMathTotalScore = 0;int nChineseTotalScore = 0; int nEnglishTotalScore = 0; printf("个人总成绩：n");for (m = 0; m < 5; m+)n StuTotalScore = 0;for

6、(n = 0; n < 3; n+)n StuTotalScore += StuScorem n;switch (n)case 1: n Chi neseTotalScore += StuScorem1; break;case 2:nEn glishTotalScore += StuScorem2;switch （m）case 0:printf（"张同学：dn", nStuTotalScore）; break;case 1:pri ntf（"王同学：%dn", n StuTotalScore）; break;case 2:pri ntf（"

7、;李同学：%dn", n StuTotalScore）; break;case 3:pri ntf（"赵同学：%dn", n StuTotalScore）; break;case 4:pri ntf（"周同学：%dn", n StuTotalScore）; break;pri ntf("小组数学总分：%d小组数学平均分：%.2fn",nM athTotalScore,（double ）nMathTotalScore / 5）;pri ntf("小组语文总分：%d小组语文平均分：%.2fn",nChines

8、eTotalScore, （double ）nChineseTotalScore / 5）;printf("小组英语总分：d小组英语平均分：%.2fn"nEn glishTotalScore, (double) nEn glishTotalScore / 5);'无参函数#i nclude <stdio.h>void func()pri ntf("这是我的第一个函数！n ”)；void main()fun c();有参函数调用无参函数#i nclude <stdio.h>void func( int x, int y)int sum

9、 = x + y;printf( "x+y=%dn", sum);void main()fun c(3, 5);函数调用及返回过程#include <stdio.h>int func( int x, int y)return x + y;void main()int sum = func(3, 5);printf( "x+y=%dn", sum);Printf 函数#include <stdio.h>void main()printf( "%c %c", 'H' , 'n');p

10、ri ntf("%s", "Hellow,world!n" );pri ntf("%d %d %d n" ,1,2, 3);pri ntf("%f %f %f n",2.1, 2.2);Scanf函数#include <stdio.h>void main()char str256;/字符数组保存得到的字符串scanf( "%s", str);printf( "%sn" , str);嵌套函数#include <stdio.h>int max2( int

11、 a, int b)/用于比较两个整数大小的函数if ( a > b)return a;elsereturn b;int max4( int a, int b, int c, int d) /用于比较四个整数大小的函数 int res;res = max2( a,b);res = max2(res,c);res = max2(res,d);return res;void main()int a = 5, b = 7, c = 9, d = 22, max;printf("请输入四个整数：5 7 9 22 n");/seanf("%d %d %d %d&quo

12、t;, a=5, b=7, c=9, d=22);max = max4(a, b, e, d);printf( "max=%d n", max);递归调用#include <stdio.h>/下面的函数使用递归实现，求1n的和int getsum( int n)if ( n = 1)return 1;/满足条件，递归结束int temp = getsum( n - 1);/在函数体中调用自身return temp + n;void main()int sum = getsum(4); /调用递归函数，获得 14的和 printf( "sum=%dn&q

13、uot;, sum); / 打印结果外部函数 建立源文件first.cint add( int x, int y)return x + y;建立源文件sec on d.c#include <stdio.h>extern int add( int x, int y);void main()printf( "%dn", add(1,2); _/注：extern可以省略内部函数用法建立 first.c#inelude <stdio.h> void show()printf( "%sn" , "first.c" );建

14、立 sec on d.c#in clude<stdio.h>staticvoid show()printf( "%sn" , "second.c"); void main()show();全局变量#include <stdio.h>int x = 123;void show() |printf( "show()函数中，x 的值为：%dn", x);|void main()show();printf( "main()函数中，x 的值为：%dn",x);当局部变量与全局变量重名时，全局变量会被屏

15、蔽#include <stdio.h>变量的作用域#inelude <stdio.h>int x = 10; void show() 1int x = 20;printf( "show()函数中，x 的值为：%dn", x); |void main()int x = 30;pri ntf("main()函数中，x的值为%dn", x);show(); 1If语句#include <stdio.h>void main()/定义变量xint x = 5;/如果x的值小于10则执行if大括号中的代码if (x < 10

16、)x+;printf( "x=%dn", x); lf.else 语句#include <stdio.h>void main()int num = 19;if (num % 2 = 0)/判断条件成立，num被2整除 printf( "num是一个偶数 n");elseprintf("num是一个奇数 n");lf.else if.else语句#include <stdio.h>void main()irit grade = 75;/定义学生成绩if(grade >= 80)/满足条件grsde >

17、= 80printf("该成绩的等级为优n");else if (grade >= 70)/不满足条件grade >=80,但满足条件grade>=70 printf("该成绩等级为良n");else if (grade >= 60)/不满足条件grade >=70,但满足条件grade >=60 printf("该成绩等级为中n");else/不满足条件grade >=60 printf（"该成绩的等级为差n"）;三元运算符#include <stdio.h>

18、void main()int x = 0;int y = 1;int max;max = x > y ? x : y; printf( "max = %dn");Switch语句#include <stdio.h>void main（）int week = 5;switch （week）case 1:printf（"星期一 n"）;break;case 2:printf（"星期二 n"）; break;case 3:printf（"星期三 n"）; break;case 4:printf（&quo

19、t;星期四 n"）; break;case 5:printf（"星期五 n"）; break;case 6:printf（"星期六 n"）; break;case 7:printf（"星期日 n"）;break;default :printf("输入的数字不正确.n");break;则该执行语句只需书写一一在使用switch语句过程中，如果多个case条件后面的执行语句是一样的, 次即可#include <stdio.h>void main()int week = 2;switch (week

20、)case 1:/当week满足值1、2、3、4、5中任意一个时，处理方式相同 printf（"今天是工作日n"）;break;case 6:case 7:/当week满足值6、7中任意一个时，处理方式相同 printf（"今天是休息日n"）;break;While循环语句#include <stdio.h> void main()int x = 1; while (x <= 4)printf( "x = %dn" , x); / 条件成立，打印x的值x+;/x进行自增Do-while循环语句#include <

21、;stdio.h>void main()int x = 1;/定义变量x，初始值为1doprintf("x=%dn", x）; /条件成立，打印x的值x+;x进行自增 while (x <= 4);/ 循环条件For循环#inelude <stdio.h> void main()int x = 1;/定义变量x，初始值为1doprintf("x=%dn", x); /条件成立，打印x的值x+;/x进行自增 while (x <= 4);/循环条件Break语句#include <stdio.h>void main

22、()int x = 1;/定义变量x,初始值为1while (x <= 4)/ 循环条件 |x+;/x进行自增printf( "x=%dn", x);if(x = 3)break;Goto语句#include <stdio.h>int main()int i, j;/定义两个循环变量for(i = 1; i <= 9; i+)/夕卜层循环for (j = 1; j <= i; j+)/内层循环if (i >4)/判断i的值是否大于4goto end;/跳至标志位end的语句/输出*prmtf( "*")；printf(

23、 "n" );/ 换行end: return 0;Continue 语句#include <stdio.h>void main()int sum = 0;/定义变量sum,用于记住和for ( int i = 1; i <= 100; i+)if (i % 2 = 0)/如果i是一个偶数，执行if语句中的代码sum += i;/实现sum和i的累加printf( "sum = %dn" , sum);无符号整数类型#include <stdio.h>void main()int a = 12345;long b = -234

24、56, suml;unsigned int c = 32800, sum2;suml = b - a;sum2 = c - b;printf( "sum1=%1d,sum2=%un； suml, sum2);Float和double之间的数据转换#include <stdio.h>void main()float a;a = 3.141592612;printf( "a=%.9fn" , a);字符型变量#include <stdio.h>void main()char chi = 'A ;char ch2 = 65;printf(

25、 "%cn" , ch1); printf( "%cn" , ch2);#include <stdio.h>void main()转义符的用法charch1='A'charch2='n'charch3='B'charch4=''printf( "%c", ch1);printf( "%c", ch2);printf( "%c", ch3);printf( "%c", ch4); printf( &qu

26、ot;%c", ch2);枚举类型变量#include <stdio.h>enummonth JAN=1, FEB=2, MAR3, APf=4, MAY=5,JUN=6, JUL=7, AUG8, SEP=9, OCT10,NOVM1,DE(=12;void main()enum month lastm on th, thism on th, n extm on th;lastmo nth = APRthismo nth = MAYn extm onth = JUNpr intf( "%d %d %d n" , lastm on th, thism

27、on th, n extm on th); 在枚举中规定，如果不给标识符指定具体值，会默认该标识符的值等于前一标识符的值加一。因此可以快速定义#include <stdio.h>/定义一组常量enum Constants cl, c2, c3 = 4,c4, c5 = 3,c6, c7, c8 = 'O' , c9 ;void main()printf( "c9=%dn", c9);Sizeof运算符#i nclude <stdio.h>void mai n()/通过类型名称计算各基本数据类型所占内存大小pr in tf("

28、char: %dn", sizeof(char);pri ntf("short: %dn", sizeof(short);pr in tf("l ong: %dn", sizeof(l on g);prin tf("float: %dn", sizeof(float);SB C:Vi*ind owssystem 32cmd. exec har:1: 2 long： 4 float:4double* S unsigned char： 1 unsigned short: 2 iins ign ed int *4unsigned

29、longr：4ual_int:4u al_doiu.blis« B 请按任意键继续printf("double: %dn", sizeof(double);pri ntf("u nsig ned char: %dn", sizeof(u nsig ned char); pr in tf("u nsig ned short: %dn", sizeof(u nsig ned short); pr in tf("u nsig ned int: %dn", sizeof(u nsig ned in t);pr i

30、n tf("u nsig ned long: %dn", sizeof(u nsig ned lon g);/通过变量名称计算变量所属数据类型占用内存大小 in t val i nt = 100;double val double = 100000.0;prin tf("val i nt:%dn", sizeof(val i nt);pri ntf("val_double: %dn", sizeof(val_double); _ _指针的取址和取值运算符#include <stdio.h>void main()int nu

31、m = 100;int 类型变量 numpri ntf("num=%dn", num);/ 输岀变量值pri ntf("#&num = %pn" , &num);/输出变量的内存地址pri ntf("*&num = %dn" , *&num);/通过num地址读取num中的数据指针表达式的自增自减运算#inelude <stdio.h> void main()int arr5 = 1,2,3,4,5 ;int *p1 = &arr0;int *p2 = &arr3;print

32、f( "p1 的值为：%dn" , *p1);printf( "+p1 的值为:%dn" , *(+p1);printf( "p2 的值为：%dn" , *p2);printf( "-p2 的值为:%dn" , *(-p2); 1同类指针相减运算#inelude <stdio.h>void main()int arr5 = 1,2,3,4,5 ；int *p1 = &arr0;int *p2 = &arr3;printf( "p1 的值为：%dn" , p1);pri

33、ntf( "p2 的值为：%dn" , p2);printf( "p1-p2 的值为:%dn" , p2 p1);指针变量的使用#inelude <stdio.h>void main( int arge , char * argv )int nNum = 0x12345678;int * pNum;/定义一个指针变量pNum = &n Num;/为指针变量赋值printf( "nNum Val:%xn" , nNum);printf( "nNum Addr:%pn" , &nNum);p

34、rintf( "pNum Val:%pn" , pNum);printf( "*pNum :%xn" , *pNum);指针变量作为函数的参数(作用是将一个变量的地址传送到另一个函数中)#include <stdio.h>void main( int arge , char * argv )int nNum = 0x12345678;int * pNum; /定义一个指针变量 pNum = &nNum; /为指针变量赋值 printf( "nNum Val:%xn" , nNum); printf( "n

35、Num Addr:%pn" , &nNum); printf( "pNum Val:%pn" , pNum); printf( "*pNum :%xn" , *pNum);指向一维数组元素的指针#include <stdlib.h>#include <stdio.h>void main( int argc , char * argv )int X10 = 1,2,3,4,5,6,7,8,9,10 ;int i = 0;int nLen = 10;printf("数组X修改前：n");for (

36、i = 0; i < 10; i+)printf( "%d ", Xi);/用指针pTemp指向数组Xint * pTemp = X;/通过指针pTemp访问数组中的元素，并修改元素的值for (i = 0; i < nLen; i+)pTempi = pTempi * 2;printf( "n数组X修改之后：n”)；/通过指针移动来遍历输出X数组中的元素for (i = 0; i < 10; i+)printf( "%d ", *pTemp);pTemp+;printf( "n");指向二维数组元素的指针

37、#include <stdlib.h>#inelude <stdio.h> void main()int X25 = 1,2,3,4,5 , 6,7,8,9,10 ;/定义数组指针用于指向二维数组int (*pXEIement)5 = X;int m = 0;int n = 0;printf("二维数组元素如下:n");for (m=0; m < 2; m+)printf("第4行的元素如下：n" , m + 1);for (n = 0; n < 5; n+) /通过数组指针来访问为数组中的元素 printf( &qu

38、ot; %d", pXEIeme ntm n);printf( "n");指针数组的概念#i nclude <stdio.h>/输出指针数组中元素的值int print( int * arr ,int n) Jint i = 0;for (i = 0; i< n; i+)printf( "%dn" , * arr i);return 1;void main( int argc , char * argv ) int a, b, c, d, e;a = 1;b = 2;c = 3;d = 4;e = 5;int *Arr = &

39、amp;a, &b, &c, &d, &e ;/ 定义一个 int 类型的指针数组print(Arr, 5);/ 调岀 print ()函数指针数组作为main ()函数的形参#in elude <stdlib.h>#in elude <stdio.h>int main( int argc , char * argv )int i = 0;pri ntf（"程序的参数列表如下：n “）；for (i = 0; i <argc ; i+)printf( "%s “，argv i);return 0;二级指针#in

40、elude <stdlib.h>#i nclude <stdio.h>void main( int argc , char * argv )int m=10;int * |pM = &m;/指针pM存放的是变量m的地址int *ppM = &pM;/二级指针ppM存放的是指针pM的地址pri ntf("m = %dn",m);pri ntf("*pM = %dn",*pM);pri ntf("*pM = %dn",*ppM);Malloc()函数和free ()函数#i nclude <s

41、tdio.h>void main()int u, v;/定义二维数组的长和宽printf("第一维为：")；scanf( "%d", &u);printf("第二维为：")；scanf( "%d", &v);int * array = ( int *)malloc( sizeof (int *)* u);/ 先创建第一维for (int i = 0; i < u; i+)/在内层循环中动态创建第二维arrayi = (int *)malloc(sizeof (int )*v);for (

42、int j = 0; j<v; j+)arrayij = 0;/给数组元素复制printf( "%d “，arrayij);字符数组#in clude <stdio.h>void main()/声明一个字符数组并初始化char char_array5 = 'h' , 'e' , 'l''l' , 'o' ;int i;/通过sizeof关键字得到数组长度，并遍历打印其内容。for (i = 0; i <sizeof (char_array); +i)printf("%c&

43、quot; , char_arrayi);printf( "n");输出字符串中的字符#i nclude <stdio.h>void main()hellochar char array6 = ( "hello" ); /声明一个长度为6的字符数组并初始化为int i;/通过sizeof关键字得到数组长度fc)r (i = 0; i <sizeof(char_array); +i)F/ 通过 printf输岀char array中的字符串printf( "char_.array的第 %dn", i, char_arr

44、ayi);获取用户输入字符的长度#defi ne _CRT_SECURE_NO_WARNINGS闭安全检查#include <stdio.h>#include <string.h>void main()char str1024;/声明一个足够大的字符型数组保存将要被输入的字符串printf("请输入待测量的字符串:");scanf( "%s", str); /接受用户输入字符串 printf("您输入的字符串长度为 d。n" , strlen(str);空字符 0 '的使用#include <st

45、dio.h>void main()char char_array = 'h' , 'e' , T , T , 'o' , '0' , 'w','o' , 'r' , 'l' , 'd' ;printf "%sn", char_array ;忘记在字符数组的末尾添加空字符0 '程序也会出现一些奇怪的现象#include <stdio.h>void main()char char_array = 'h&

46、#39; , 'e' , T , T , 'o' ;printf"%sn", char_array ;使用指针修改字符串中的字符#include <stdio.h>int main()char char_array = "hello world!" ;char *ptr;printf("修改前的字符串如下：%sn", char_array);ptr = char_array; /将一个字符型指针指向字符型数组 char_array 的首地址/开始修改字符串while (*ptr !='

47、;0' )/检测是否到串未尾if (*ptr ='')*ptr ='!'ptr+;printf("修改后的字符串如下：s n" , char_array);return 0;Gets ()函数#pragma warning( disable :4996) #inelude <stdio.h> void main()char pho neNumber12;printf（"请输入手机号码："）;gets(ph on eNumber);printf("您的手机号码是：sn" , phone

48、Number);Puts ()#pragma warning( disable :4996) #inelude <stdio.h>void main()char buf12;puts("请输入一个字符串：");gets(buf);puts("您输入的是：n");puts(buf);字符串比较#pragma warning( disable :4996)#include <stdio.h>#include <string.h>void main()char username100;/定义存放用户名的字符数组char pa

49、ssword100;/定义存放密码的字符数组printf("登录n");printf("请输入用户名：");gets(username);/获取用户输入的用户名printf("请输入密码:");gets(password);/获取用户输入的密码/比较输入的用户名和密码是否正确if (!strcmp(password, "ILoveC" ) && (!strcmp(username, "user")printf("用户 %s 登录成功！ n" , user na

50、me);elsen");printf("登陆失败，请检查用户名或密码是否正确输入。Strncmp ()函数#include <string.h>#include <stdio.h>voidmai n()char * str1 ="abcdef"char * str2 ="abcdeg"/判断字符串str1和str2中的前5个字符是否相同if (!strncmp(str1, str2, 5)printf( "str1 和str2 的前5个字符相同”)；elseprintf( "str1和str

51、2的前5个字符不同”);Strchr ()函数#include <stdio.h>#inelude <string.h>int getcount( char * str , char c)/存储找到的字符个数int count = 0;/存储当前字符指针在字符串中的位置char * ptr = str ;/获取第一次出现字符变量c值的指针位置while (ptr = strchr(ptr,c) != NULL+ptr;+cou nt;return count;void main()char str6 ="abaca"char c ='a

52、9;int num = getcount(str, c);printf("字符c在字符串中岀现了 d次。n" , c, num);Strstr ()函数#pragma warning( disable :4996)#include <stdio.h>#include <string.h>void main()char str10240;/声明字符串数组，用于保存段落char word10240;/声明字符串数组，用于保存要查找的字符串char * ptr;printf("请输入要扫描的段落：");gets(str);printf(

53、"请输入要查找的单词：“)；gets(word);ptr = strstr(str, word);/搜索是否包含指定的字符串if (ptr = NULLprintf（"段落中不包含单词 s。n" , word）; else/得到检测岀的字符串后20个字符if (strlen(ptr) >= 20)printf("单词岀现在%s附近。n“，ptr);Strcat ()函数#pragma warning( disable :4996)#include <stdio.h>#include <string.h>void main()

54、/区号char areaNumber5;/电话号码char pho neNumber12;int in put;/分机号char extraNumber5;/用来存储连接后的结果，需要初始化为0!char buffer25 = 0 ;printf("请输入区号:");gets(areaNumber);printf("请输入电话号码:");gets(ph on eNumber);printf("有分机号吗？ ( y/n)");in put = getchar();/由于getchar ()只读入一个字符，因此需要调用fflush来清除输

55、入缓冲区的换行符fflush( stdin );if (input ='y')printf("请输入分机号：“)；gets(extraNumber);strcat(buffer, areaNumber);strcat(buffer,"-");strcat(buffer, pho neNumber);strcat(buffer,"-");strcat(buffer, extraNumber);elsestrcat(buffer, areaNumber);strcat(buffer, "-");strcat(bu

56、ffer, pho neNumber);printf("您的电话号码是 s。n"buffer);Str neat ()函数#pragma warning( disable :4996)#include <stdio.h>#include <string.h>void main()char buf130;/声明字符串数组，用于保存字符串 bufl.char buf230;/声明字符串数组，用于保存字符串 buf2.printf（"请输入第一个字符串：“）；gets（bufl）;printf（"请输入第二个字符串：“）；gets(bu

57、f2);/ 使用 strncait（）函数来对字符串进行拼接strncat(buf1, buf2,sizeof (buf1)-1 - strlen(buf1);printf（"连接后的字符串是 s。n" , bufl）;Atoi ()函数#pragma warning( disable :4996)#include <stdio.h>#include <stdlib.h>void main()char buf20;int result;printf("请输入待转换的十进制数：");gets(buf);result = atoi(buf);printf("转换结果是 d. n" , result);使用函数itoa ()将整数转换字符串#pragma warning( disable :4996)#include <stdio.h>#include <stdlib.h>/用于保存八进制的转换结果char number_820;/用于保存十进制的转换结果char numb