Questions about the fopen function has no return value-CodePudding

I use the official tutorials, still returns null Pointers, have a great god know what's going on? Vc + + under several versions,

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Buf array has the assignment

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3

E: \ \ 1. TXT

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refer to the second floor truth is right or wrong response:

3

E: \ \ 1. TXT

The first is not to add the diagonal the return value is NULL, but the second one is correct, why not return a value?

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Fopen parameters with the 'r' to read the way open, then your file must exist, see the buf value is literally input of
In addition fopen success open file corresponding to the use fclose

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1, e: \ aaaa. TXT said is wrong name string, because in c \ means escape characters such as \ n for the return,,,
2, to determine whether the file is there, and there are no other applications,

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reference 4 floor zgl7903 response:

fopen parameters with the 'r' to read the way open, then your file must exist, see the buf value is literally input of
Another fopen successful open file corresponding to the use fclose

version version of the adult, what do you mean if is to use R file must be inside the hard disk? In the memory can't?