How to read the file in my PC,should I change my code?The file is C:\123.txt

Question

void main(void)
{
    FILE *fp;
    fp = fopen("C:\\123.txt","r");
    if(!fp){
        printf("檔案開啟失敗!!");
        return;
    }
    
    int count = 0;
    char c;
    while((c = getc(fp)) != EOF){
        if(c == 'A')
            count ++ ;
    }
    
    printf("A的數量為%d",count);
    fclose(fp);
}

Answer 1

I guess you run into the problem of not being able to open the file.

This is because you need to escape special characters in strings, such as backslash. So your path correctly escaped would be:

FILE * fp = fopen("C:\\123.txt", "r");

Comments

Thank you for your answer. But after I modified the code to fopen("C:\\123.txt", "r"), reading the file still failed.

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thank you! It was very helpful for me!

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Can you share your code (there is an orange SHARE) button on the code editor page if you still have an issue?

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The following code is my code still run to printf("檔案開啟失敗!!")：
(Maybe it's because the program is executed in the browser?)


#include <stdio.h>

void main(void)
{
    FILE *fp;
    fp = fopen("C:\\123.txt","r");
    if(!fp){
        printf("檔案開啟失敗!!");
        return;
    }
    
    int count = 0;
    char c;
    while((c = getc(fp)) != EOF){
        if(c == 'A')
            count ++ ;
    }
    
    printf("A的數量為%d",count);
    fclose(fp);
}

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That's right.

That code will run on the server, not on your local machine. There's no file on the path C:\123.txt on the server.

You can add files to your project (any file, even the 123.txt) with the NEW FILE or UPLOAD FILE button just left to the green RUN button. Those files will be available when you run your code.

In that case, you relative paths, not absolute paths, that is, fopen("123.txt", "r").

Good luck!

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Thank you, this problem is perfectly solved.