C语言编译出现 incompatible implicit declaration of built-in function ‘strlen’等

C语言 编译时出现错误

warning: incompatible implicit declaration of built-in function ‘malloc’
warning: incompatible implicit declaration of built-in function ‘bzero’
warning: incompatible implicit declaration of built-in function ‘strncpy’
warning: incompatible implicit declaration of built-in function ‘strlen’

warning: incompatible implicit declaration of built-in function ‘memcpy’

warning: incompatible implicit declaration of built-in function ‘memset’

解决办法：

        加入头文件即可

#include<stdlib.h>

#include<string.h>