c语言出现Use of undeclared identifier 问题是设置错误造成的,解决方法为:
1、遇到警告Use of undeclared identifier ‘p’ ...就是说这里有无法识别的p。
![](https://iknow-pic.cdn.bcebos.com/f2deb48f8c5494eec01d6e653df5e0fe99257e8a?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
2、可以直接找到这个p值。p下面有一个_,说明就是该处出错。
![](https://iknow-pic.cdn.bcebos.com/5d6034a85edf8db1f1111d181923dd54564e748a?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
3、要是该p值不用的话就直接删掉,若是需要用的话就直接声明好了,很有可能声明的时候出错,往上面的代码找一下。
![](https://iknow-pic.cdn.bcebos.com/a71ea8d3fd1f4134c7086402351f95cad1c85e8a?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
4、这里就是直接删掉p这个值,因为该值以后的代码里是不到的。
![](https://iknow-pic.cdn.bcebos.com/f9dcd100baa1cd111389135ca912c8fcc3ce2d8a?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
5、Unused variable 'arr'.就是arr该数组没有被使用。假如不用可以删掉,需要的话等后面的代码应用了就不会出现警告了。
![](https://iknow-pic.cdn.bcebos.com/c2fdfc039245d688be3dd3d8b4c27d1ed21b248a?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)