This function or variable may be unsafe. Consider using scanf_s instead.

去掉安全检查，开头加上即可：

1 #define _CRT_SECURE_NO_WARNINGS

或者：

严重性代码说明项目文件行禁止显示状态

错误C4996 'scanf': This function or variable may be unsafe. Consider using scanf_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.hellof:\users\denggelin\documents\visual studio 2015\projects\hello\hello\源.c6

This function or variable may be unsafe. Consider using scanf_s instead.

右键项目，属性

预处理器，预处理器定义，编辑

新增："_CRT_SECURE_NO_WARNINGS"

确定。