C语言程序实例.doc

数组的引用：#includevoid 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：#includevoid main(int argc, char *argv)int x5 = 1,2,3,4,5 ;int i = 0;for (i = 0; i 5; i+)printf(x%d:%dn, i, xi);一维数组的最值：#includeint main(int argc, char* argv)int x5 = 1,2,3,4,5 ;int nMax = x0;int i = 0;for (i = 1; i nMax)nMax = xi;printf(max:%dn, nMax);return 0;一维数组排序：#includevoid main(int argc, char * argv)int arr5 = 9, 8, 3, 5, 2 ;int temp = 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 arrj + 1) temp = arrj;arrj = arrj + 1;arrj + 1 = temp; printf(冒泡排序后： n); for (i = 0; i 5; i+) printf(%d , arri); printf(n);二维数组的遍历#includevoid 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(%d%d: %d , i, j, arrayij);printf(n);/每一行的末尾添加换行符二维数组应用#include void main(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+)nStuTotalScore = 0;for (n = 0; n 3; n+)nStuTotalScore += StuScoremn;switch (n)case 0:nMathTotalScore += StuScorem0;break;case 1:nChineseTotalScore += StuScorem1;break;case 2:nEnglishTotalScore += StuScorem2;switch (m)case 0:printf(张同学：%dn, nStuTotalScore);break;case 1:printf(王同学：%dn, nStuTotalScore);break;case 2:printf(李同学：%dn, nStuTotalScore);break;case 3:printf(赵同学：%dn, nStuTotalScore);break;case 4:printf(周同学：%dn, nStuTotalScore);break;printf(小组数学总分：%d 小组数学平均分：%.2fn,nMathTotalScore, (double)nMathTotalScore / 5);printf(小组语文总分：%d 小组语文平均分：%.2fn,nChineseTotalScore, (double)nChineseTotalScore / 5);printf(小组英语总分：%d 小组英语平均分：%.2fn,nEnglishTotalScore, (double)nEnglishTotalScore / 5);无参函数#include void func()printf(这是我的第一个函数！n);void main()func();有参函数调用无参函数#include void func(int x, int y)int sum = x + y;printf(x+y=%dn, sum);void main()func(3, 5);函数调用及返回过程#includeint func(int x, int y)return x + y;void main()int sum = func(3, 5);printf(x+y=%dn, sum);Printf函数#includevoid main()printf(%c %c, H, n);printf(%s, Hellow,world!n);printf(%d %d %d n,1, 2, 3);printf(%f %f %f n,2.1, 2.2);Scanf 函数#includevoid 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#includeint max2(int 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);/scanf(%d %d %d %d, a=5, b=7, c=9, d=22);max = max4(a, b, c, d);printf(max=%d n, max);递归调用#include/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, 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second.c#includeextern 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#includevoid show()printf(%sn, first.c);建立second.c#includestatic void show()printf(%sn, second.c);void main()show();全局变量#includeint 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，全局变量会被屏蔽#includeint x = 789;void main()int x =123;printf(x的值为：%dn,x);变量的作用域#includeint x = 10;void show()int x = 20;printf(show()函数中，x的值为：%dn, x);void main()int x = 30;printf(main()函数中，x的值为%dn, x);show();If 语句 #includevoid 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)x+;printf(x=%dn, x);If.else语句#includevoid 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);If.else if.else语句#includevoid main()int grade = 75;/定义学生成绩if (grade = 80)/满足条件grsde = 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=70printf(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 =60printf(该成绩等级为中n);else/不满足条件 grade =60printf(该成绩的等级为差n);三元运算符#includevoid main()int x = 0;int y = 1;int max;max = x y ? x : y;printf(max = %dn);Switch 语句#includevoid 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(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;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，则该执行语句只需书写一次即可#includevoid main()int week = 2;switch (week)case 1:case 2:case 3:case 4:case 5:/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#includevoid 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#includevoid 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#includevoid 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#includevoid main()int x = 1; /定义变量x，初始值为1while (x = 4) /循环条件printf(x=%dn, x);if (x = 3)break;x+; /x进行自增 Goto语句#includeint main() int i, j; /定义两个循环变量for (i = 1; i = 9; i+) /外层循环for (j = 1; j 4) /判断i的值是否大于4goto end; /跳至标志位end的语句printf(*); /输出*printf(n); /换行end: return 0;Continue 语句#includevoid 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continue; /结束本次循环sum += i; /实现sum和i的累加printf(sum = %dn, sum);无符号整数类型#includevoid main()int a = 12345;long b = -23456, sum1;unsigned int c = 32800, sum2;sum1 = b - a;sum2 = c - b;printf(sum1=%1d,sum2=%un, sum1, sum2);Float 和double之间的数据转换#includevoid main()float a;a = 3.141592612;printf(a=%.9fn, a);字符型变量#includevoid main()char ch1 = A;char ch2 = 65;printf(%cn, ch1);printf(%cn, ch2);#includevoid main()转义符的用法char ch1 = A;char ch2 = n;char ch3 = B;char ch4 = ;printf(%c, ch1);printf(%c, ch2);printf(%c, ch3);printf(%c, ch4);printf(%c, ch2);枚举类型变量#includeenum month JAN=1,FEB=2,MAR=3,APR=4,MAY=5,JUN=6, JUL=7,AUG=8,SEP=9,OCT=10,NOV=11,DEC=12;void main()enum month lastmonth, thismonth, nextmonth;lastmonth = APR;thismonth = MAY;nextmonth = JUN;printf(%d %d %d n, lastmonth, thismonth, nextmonth); 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/定义一组常量enum Constants c1, c2, c3 = 4, c4, c5 = 3, c6, c7, c8 = 0, c9 ;void main()printf(c9=%dn, c9);Sizeof 运算符#include void main()/通过类型名称计算各基本数据类型所占内存大小printf(char: %dn, sizeof(char);printf(short: %dn, sizeof(short);printf(long: %dn, sizeof(long);printf(float: %dn, sizeof(float);printf(double: %dn, sizeof(double);printf(unsigned char: %dn, sizeof(unsigned char);printf(unsigned short: %dn, sizeof(unsigned short);printf(unsigned int: %dn, sizeof(unsigned int);printf(unsigned long: %dn, sizeof(unsigned long);/通过变量名称计算变量所属数据类型占用内存大小int val_int = 100;double val_double = 100000.0;printf(val_int: %dn, sizeof(val_int);printf(val_double: %dn, sizeof(val_double);指针的取址和取值运算符#includevoid main()int num = 100; /int类型变量numprintf(num=%dn, num); /输出变量值printf(#&num = %pn, &num); /输出变量的内存地址printf(*&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#includevoid main()int arr5 = 1,2,3,4,5 ;int *p1 = &arr0;int *p2 = &arr3;printf(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);同类指针相减运算#includevoid main()int arr5 = 1,2,3,4,5 ;int *p1 = &arr0;int *p2 = &arr3;printf(p1的值为： %dn, p1);printf(p2的值为： %dn, p2);printf(p1-p2的值为: %dn, p2-p1);指针变量的使用#includevoid main(int argc,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(nNum Addr:%pn, &nNum);printf(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）#includevoid main(int argc,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(nNum Addr:%pn, &nNum);printf(pNum Val:%pn, pNum);printf(*pNum :%xn, *pNum);指向一维数组元素的指针#include#includevoid 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 (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#include#includevoid 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(*pXElement)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%d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( %d, pXElementmn);printf(n); 指针数组的概念#include/输出指针数组中元素的值int print(int *arr, int n)if (!arr)return 0;int i = 0;for (i = 0; in; i+)printf(%dn, *arri);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 = &a, &b, &c, &d, &e ;/定义一个int类型的指针数组print(Arr, 5);/调出print（）函数指针数组作为main（）函数的形参#include#includeint main(int argc, char * argv)int i = 0;printf(程序的参数列表如下：n);for (i = 0; i argc ; i+)printf(%s , argvi);return 0;二级指针#include#includevoid 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printf(m = %dn, m);printf(*pM = %dn, *pM);printf(*pM = %dn, *ppM);Malloc()函数和free（）函数#includevoid 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(int j = 0; jv; j+)arrayij = 0; /给数组元素复制printf(%d , arrayij);字符数组#includevoid 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, char_arrayi);printf(n);输出字符串中的字符#includevoid main()char char_array6 = (hello);/声明一个长度为6的字符数组并初始化为helloint i;/通过sizeof关键字得到数组长度for (i = 0; i sizeof(char_array); +i)/通过printf输出char_array中的字符串printf(char_array的第%dn, i, char_arrayi);获取用户输入字符的长度#define _CRT_SECURE_NO_WARNINGS /关闭安全检查#include#includevoid 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#includevoid main()char char_array = h, e, l, l, 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#includevoid main()char char_array = h, e, l, l, o ;printf %sn, char_array ;使用指针修改字符串中的字符#includeint 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 != 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)#includevoid main()char phoneNumber12;printf(请输入手机号码：);gets(phoneNumber);printf(您的手机号码是: %sn, phoneNumber);Puts（）#pragma warning(disable:4996)#includevoid 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#includevoid main()char username100; /定义存放用户名的字符数组char password100; /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, username);elseprintf(登陆失败，请检查用户名或密码是否正确输入。n);Strncmp（）函数#include#includevoid main()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str2的前5个字符不同);Strchr（）函数#include#includeint 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;+count;return count;void main() char str6 = abaca;char c = a;int num = getcount(str, c);printf(字符%c在字符串中出现了%d次。n, c, num);Strstr（）函数#pragma warning(disable:4996)#include#includevoid 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(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 = NULL)printf(段落中不包含单词 %s。n, word);else/得到检测出的字符串后20个字符if (strlen(ptr) = 20)ptr20 = 0;printf(单词出现在 %s附近。n, ptr);Strcat（）函数#pragma warning(disable:4996)#include#includevoid main()/区号char areaNumber5;/电话号码char phoneNumber12;int input;/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(phoneNumber);printf(有分机号吗？（y/n);input = getchar();/由于getchar（）只读入一个字符，因此需要调用fflush来清除输入缓冲区的换行符fflush(stdin);if (input = y)printf(请输入分机号：);gets(extraNumber);strcat(buffer, areaNumber);strcat(buffer, -);strcat(buffer, phoneNumber);strcat(buffer, -);strcat(buffer, extraNumber);elsestrcat(buffer, areaNumber);strcat(buffer, -);strcat(buffer, phoneNumber);printf(您的电话号码是 %s。n,buffer)