C - 逐行读取文件

Question

The code is running well, it's just that I feel there are still many mistakes and give me a little direction to improve in the future. I want to learn how to maintain the code properly.

fix the code as it should!

Data.txt

[1] Line numbers 1.
[2] Line numbers 2.
[3] Line numbers 3.
[4] Line numbers 4.
[5] Line numbers 5.
[6] Line numbers 6.

My code:

#include <stdio.h>
#include <stdlib.h>

int getLengthFile(char *namafile)
{
    FILE *fptr;
    int n =0;
    fptr = fopen(namafile, "r");
    if(fptr != NULL){
        char c;
        while((c = getc(fptr)) != EOF) {
            ++n;
        }
        fclose(fptr);
    }
    return n;
}

int main(){
    FILE *fptr;
    int i;
    fptr = fopen("Data.txt","r");
    if(fptr != NULL){
        printf("Succes reads file!\n");
        if(getLengthFile("Data.txt")>0){
            char strLine[225];
            while(fgets(strLine,225,fptr) != NULL){
                printf("%s",strLine);
            }
        }else{
            printf("File is empty!\n");
        }
        fclose(fptr);
    }else{
        printf("Error reads file!\n");
    }

    return 0;
}

Answer 1

Here is a more or less fixed version of the code presented in the first edition of the question, where the getLengthFile() function was not present. In my opinion, that function does not provide useful functionality. If you must report that the file contained no data, you could do so by counting the number of times fgets() returns any data — if it returns any data, the file was not empty.

#include <stdio.h>

int main(void)
{
    const char filename[] = "Data.txt";
    FILE *fptr = fopen(filename, "r");
    if (fptr == NULL)
    {
        fprintf(stderr, "Error opening file %s for reading!\n", filename);
        return 1;
    }
    printf("Success opening file %s for reading\n", filename);
    char strLine[225];
    while (fgets(strLine, sizeof(strLine), fptr) != NULL)
        printf("%s", strLine);
    fclose(fptr);

    return 0;
}

When there is no file Data.txt , example output is:

Error opening file Data.txt for reading!

When there's a file containing one short line of data, example output is:

Success opening file Data.txt for reading
data from the file Data.txt

I also tested it on a file with longer lines, including lines with as many as 380 characters, and the output from the program was the same as the input except for the line saying 'Success opening file Data.txt for reading'.