C语言程序实例

#include<stdio.h>void main (int argc,char *argv[] ) {int x[5] = { 2,3,1,4,6 };int i;for (i = 0; i < 5; i++){printf("%d\n", 2 * x[i]);}}一维数组的遍历：#include<stdio.h>void main(int argc, char *argv[]) {int x[5] = { 1,2,3,4,5 };int i = 0;for (i = 0; i < 5; i++){printf("x[%d]:%d\n", i, x[i]);}}一维数组的最值：#include<stdio.h>int main(int argc, char* argv[]) {int x[5] = { 1,2,3,4,5 };int nMax = x[0];int i = 0;for (i = 1; i < 5; i++){if (x[i] > nMax){nMax = x[i];}}printf("max:%d\n", nMax);return 0;}#include<stdio.h>void main(int argc, char ** argv[]){int arr[5] = { 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 ", arr[i]);}printf(" \n");for (i = 0; i < 5-1; i++){for (j = 0; j < 5 - 1 - i; j++){if (arr[j] > arr[j + 1]){temp = arr[j];arr[j] = arr[j + 1];arr[j + 1] = temp;}}}printf("冒泡排序后： \n");for (i = 0; i < 5; i++){printf("%d ", arr[i]);}printf("\n");}二维数组的遍历#include<stdio.h>void main(){//声明并初始化数组int array[3][4] = { {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, array[i][j]); }printf("\n");//每一行的末尾添加换行符}}二维数组应用#include<stdio.h>void main(int argc, char * argv[]){int StuScore[5][3] = {//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 += StuScore[m][n];switch (n){case 0:{nMathTotalScore += StuScore[m][0];break;}case 1:{nChineseTotalScore += StuScore[m][1];break;}case 2:{nEnglishTotalScore += StuScore[m][2];}}}switch (m){case 0:{printf("张同学：%d\n", nStuTotalScore);break;}case 1:{printf("王同学：%d\n", nStuTotalScore);break;}case 2:{printf("李同学：%d\n", nStuTotalScore);break;}case 3:{printf("赵同学：%d\n", nStuTotalScore);break;}case 4:{printf("周同学：%d\n", nStuTotalScore);break;}}}printf("小组数学总分：%d 小组数学平均分：%.2f\n", nMathTotalScore, (double)nMathTotalScore / 5);printf("小组语文总分：%d 小组语文平均分：%.2f\n", nChineseTotalScore, (double)nChineseTotalScore / 5);printf("小组英语总分：%d 小组英语平均分：%.2f\n", nEnglishTotalScore, (double)nEnglishTotalScore / 5);}无参函数#include<stdio.h>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<stdio.h>void func(int x, int y){int sum = x + y;printf("x+y=%d\n", sum);}void main(){func(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=%d\n", sum);}Printf函数#include<stdio.h>void 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#include<stdio.h>void main(){char str[256]; //字符数组保存得到的字符串scanf("%s", str);printf("%s\n", str);}嵌套函数#include<stdio.h>int max2(int a, int b) //用于比较两个整数大小的函数{if (a > b){return a;}else{return 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<stdio.h>//下面的函数使用递归实现，求1~n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1~4的和printf("sum=%d\n", 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#include<stdio.h>externint add(int x, int y);void main(){printf("%d\n", add(1, 2));}//注：extern 可以省略内部函数用法建立first.c#include<stdio.h>void show(){printf("%s\n", "first.c");}建立second.c#include<stdio.h>staticvoid show(){printf("%s\n", "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：%d\n", x); }void main(){show();printf("main()函数中，x的值为：%d\n",x);}当局部变量与全局变量重名时，全局变量会被屏蔽#include<stdio.h>int x = 789;void main(){int x =123;printf("x的值为：%d\n",x);}变量的作用域#include<stdio.h>int x = 10;void show(){int x = 20;printf("show()函数中，x的值为：%d\n", x); }void main(){int x = 30;printf("main()函数中，x的值为%d\n", x); show();}If 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){x++;}printf("x=%d\n", x);}If...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");}else{printf("num是一个奇数\n");}}If...else if...else语句#include<stdio.h>void 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");}elseif (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");}elseif (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 >=60printf("该成绩的等级为差\n");}}三元运算符#include<stdio.h>void main(){int x = 0;int y = 1;int max;max = x > y ? x : y;printf("max = %d\n");}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("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#include<stdio.h>void 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#include<stdio.h>void main(){int x = 1;while (x <= 4){printf("x = %d\n", x);//条件成立，打印x的值x++; //x进行自增}}Do-while 循环语句#include<stdio.h>void main(){int x = 1; //定义变量x，初始值为1do{printf("x=%d\n", 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#include<stdio.h>void main(){int x = 1; //定义变量x，初始值为1do{printf("x=%d\n", 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(){int x = 1; //定义变量x，初始值为1while (x <= 4) //循环条件{printf("x=%d\n", x);if (x == 3){break;}x++; //x进行自增}}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++) //外层循环{for (j = 1; j <= i; j++) //内层循环{if (i >4) //判断i的值是否大于4{goto end; //跳至标志位end的语句}printf("*"); //输出*printf("\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{continue; //结束本次循环}sum += i; //实现sum和i的累加}printf("sum = %d\n", sum);}无符号整数类型#include<stdio.h>void main(){int a = 12345;long b = -23456, sum1;unsignedint c = 32800, sum2;sum1 = b - a;sum2 = c - b;printf("sum1=%1d,sum2=%u\n", sum1, sum2);}Float 和double之间的数据转换#include<stdio.h>void main(){float a;a = 3.141592612;printf("a=%.9f\n", a);字符型变量#include<stdio.h>void main(){char ch1 = 'A';char ch2 = 65;printf("%c\n", ch1);printf("%c\n", ch2);}#include<stdio.h>void 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#include<stdio.h>enum 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。