C-Getchar在嵌套的while循环中导致无限循环

Question

I'm currently trying count the number of characters in a text file excluding line comments (like //comment), so I'm trying to identify the start of a comment (//) and use a while loop to read the comment until I encounter a EOF or new line character, thus I know that the comment has ended. The problem is that when I'm using a double while loop() to filter out line comments, it causes an infinite loop, because it will not exit the inner while loop. Here is my code. Does anyone have any ideas as to why this is happening? I'm stumped.

int numChars = 0;
int c = 0;
int prevc = 0;

while ((c = getchar()) != EOF) {
        if (c == '/' && prevc == c) {
            while (c != '\n' || c != EOF) {
                c = getchar();
            }
        }

    numChars++;
    prevc = c;
}

For instance, if the text file were to contain //Hello, it should output 0 chars, while if the text file contains Hello it should output 5 chars.

Answer 1

c != '\\n' || c != EOF c != '\\n' || c != EOF is always true.

It could only be false if both conditions were false, which would mean that both c == '\\n' and c == EOF were true. Obviously, those two cannot both be true (unless EOF were the same as '\\n' , which it isn't).

You need to use && , not || .

Answer 2

This statement is always true.

while (c != '\n' || c != EOF)

Hence an infinite loop.