Chinese characters show up on txt file after fwrite

Question

I want to write data in structure to a text file. But it ends up showing strange characters in the text file. I have changed many forms of fwrite arguments but none works. Please someone help me. Sorry for the long code

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

struct Student
{
    char name[30];
    int id;
    int score;
    int score2;
    int score3;
};

int main()
{
    printf("Please input the information below into grade.data!\n");
    printf("Ends with name's value equal to 'E'\n");
    struct Student stu[10];
    int i = 0, maxlength = 0; //size of longest name
    printf("Name No Math Chi Eng\n");
    while (true){
        scanf("%s", stu[i].name);
        if(maxlength < strlen(stu[i].name)) maxlength = strlen(stu[i].name);
        if (stu[i].name[0] == 'E') break;
        scanf("%d", &stu[i].id);
        scanf("%d", &stu[i].score1);
        scanf("%d", &stu[i].score2);
        scanf("%d", &stu[i].score3);
        i++;
    }

    FILE* fp;
    fp = fopen("test.txt", "wb");
    if (fp == NULL) {
        printf("Open file error!");
        exit(-1);
    }

    fwrite(&stu, sizeof(struct Student), 1, fp);
    fclose(fp);
    printf("Name%-*c No%-*c Math Chi Eng\n", maxlength-4, ' ', 7, ' ');
    for (int i = 0; stu[i].name[0] != 'E'; i++) {
        printf("%-*s ", maxlength, stu[i].name);
        printf("%-*d ", 9, stu[i].id);
        printf("%-*d ", 4, stu[i].score1);
        printf("%-*d ", 3, stu[i].score2);
        printf("%d\n", stu[i].score3);
    }
    return 0;
}

*I want to write data in **structure** to a **text file*** A structure is not text. `fwrite()` writes the raw byte contents. — Andrew Henle, Mar 05 '20 at 14:57
It's more idiomatic to iterate over an array of structs with: `for( struct Student *p=stu; p < stu + 10; p++) scanf("%s", p->name); ...` The s[i].m notation gets unwieldy very quickly. `->` is your friend. — William Pursell, Mar 05 '20 at 15:20
It will write the structure to a file but not in a human readable format. You can use fread to read the data back. On Linux, use od to look at the file, on windows have a look at https://stackoverflow.com/questions/1724586/can-i-hex-edit-a-file-in-visual-studio on how to view a binary file — cup, Mar 05 '20 at 15:31
Using `scanf()` to read (potentially malformed) user input, without checking return code -> UB waiting to happen. You don't *know* what's in `stu` after your input. You might be looking at uninitialized values. — DevSolar, Mar 06 '20 at 08:13

score 0 · Answer 1 · edited Mar 06 '20 at 08:34

0

It because members in the structure Student other than name are integers. Convert integer values to ASCII and then store it in the file.

edited Mar 06 '20 at 08:34

Valerii Boldakov

1,751
9
19

answered Mar 06 '20 at 08:10

alagesan

1
2

Chinese characters show up on txt file after fwrite

1 Answers1