1、首先建头文件是为了声明c文件中的函数,以及包括宏定义。建立头文件要有对应的c文件。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/34fae6cd7b899e512973bf4c4da7d933c9950dec?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
2、要写头文件首先要建一个.h文件。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/5bafa40f4bfbfbed9fb7b32777f0f736aec31fff?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
3、打开h文件,进行编辑。建立头文件是有一定步骤的。要用到#ifndef。。。#define。。。。#endif。这是为了避免重复定义。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/95eef01f3a292df53864294db3315c6035a873c7?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
4、#ifndef后面要写的是头文件名称的大写。例如:test.h要写成__TEST_H__。前面与后面是两个下划线。字母用大写。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/738b4710b912c8fcc9cb7395f3039245d68821a9?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
5、然后在define与endif中间声明函数名,记得写冒号。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/aec379310a55b319d7c1072d4ca98226cffc17a9?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
6、然后在main文件中写上include这个头文件,就可以调用了。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/1c950a7b02087bf46e4ad2b1fdd3572c10dfcfc0?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
7、最后编译,运行,就完成了。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/55e736d12f2eb9385f84ffaada628535e4dd6ff9?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)