c语言视频学习笔记（第四天）

6.1 Switch语句

#include
int main(void)
{unsigned age;printf("Please input a number:(tupe integer):\n");int result &＃61; scanf_s("%3u",&age);if (result &＃61;&＃61; 0) {printf("请输入合法数据&＃xff01;\n");return 0;}switch (age) {case 40:printf("恭喜&＃xff01;中奖了&＃xff0c;四十岁大礼包&＃xff01;赠送房子&＃xff01;\n");break;case 50:printf("恭喜&＃xff01;中奖了&＃xff0c;五十岁大礼包&＃xff01;奖励苹果&＃xff01;\n");break;case 70:printf("恭喜&＃xff01;退休&＃xff01;Goodbye\n");break;default:printf("没找到您的年龄&＃xff0c;可能您的年龄没有准备礼包\n");break;}return 0;
}

6.2   &＃xff1f;&＃xff1a;三元运算符 

#include
int main(void)
{int number &＃61; 9;(number &＃61;&＃61; 10) ? printf("没毛病&＃xff01;\n") : printf("有问题!\n");//如果()内判断为真&＃xff0c;则执行&＃xff1a;前的语句&＃xff0c;如果()内判断为假&＃xff0c;则执行&＃xff1a;后的语句return 0;
}

6.3  char型变量

#include
int main(void)
{char character &＃61; &＃39;A&＃39;;//注意单个字节的符号用单引号表示printf("character &＃61; %c\n", character);return 0;
}

7.1  ASCII 码

计算机内部无法储存字符&＃xff0c;所有字符都是对应一个int型整数存储在计算机内部的。 

#include
int main(void)
{char character &＃61; &＃39;A&＃39;;//注意单个字节的符号用单引号表示printf("character &＃61; %d\n", character);return 0;
}

 8.1 while循环

#include
#define ONE_KILOMETER 1000
int main(void)
{int run_meter &＃61; 0;while (run_meter <&＃61; ONE_KILOMETER) {printf("running...%d\n", run_meter);run_meter&＃43;&＃43;;}printf("我他妈终于跑完了&＃xff01;\n");
}

 continue&＃xff1a;跳过本次循环&＃xff0c;继续执行下一次循环。

#include
#define GOLD 1000
int main(void)
{int rush &＃61; 1;while (rush <&＃61; GOLD) {if (rush &＃61;&＃61; 500) {printf("挖到铁矿&＃xff01;&＃xff01;&＃xff01;扔掉不要&＃xff01;\n");rush&＃43;&＃43;;//注意不要漏掉自增变量这条语句&＃xff0c;否则将一直执行if语句continue;}printf("rush &＃61; %d\n", rush);rush&＃43;&＃43;;}printf("挖完了&＃xff01;\n");return 0;
}

8.2 do while循环

注意&＃xff1a;do while循环语句最后有分号&＃xff0c;而while循环语句最后没有分号。

先执行do循环中的内容&＃xff0c;后判断&＃xff0c;判断结果如果是true&＃xff0c;那么继续执行do中的代码块

#include
#define GOLD 1000
int main(void)
{int rush &＃61; 1;do {rush&＃43;&＃43;;printf("rush &＃61; %d\n", rush);} while (rush <&＃61; 1000);return 0;
}