CODEWITHSUNDEEP
c
Amir
Amir

Reputation: 2258

Reading from binary file in C

I have the following struct:

struct Records
{
    int Number;
    char Name[20];
    float Salary;
};

Writing two records using:

fwrite(&MyRecords.Number, sizeof(&MyRecords.Number), 1, binaryfile);
fwrite(&MyRecords.Name, sizeof(&MyRecords.Name), 1, binaryfile);
fwrite(&MyRecords.Salary, sizeof(&MyRecords.Salary), 1, binaryfile);

After writing, Im having trouble reading from it.

FILE * read;
read = fopen("binaryfile.dat","rb");

for(int x =0;x<2;x++)
{
fread(&records.Number, sizeof(records.Number), 1, read);
fread(&records.Name, sizeof(records.Name), 1, read);
fread(&records.Salary, sizeof(records.Salary), 1, read);
printf("%d %s %f\n",records.Number,records.Name,records.Salary);
}

The first line gets printed twice, and the float comes out as some weird number. I've double and tripled checked for the past 2 hours yet I cant find out what im doing wrong :(

Upvotes: 0

Views: 228

Answers (2)

AndersK
AndersK

Reputation: 36082

You could write the whole struct in one go instead, makes it easier to read:

fwrite(&MyRecords, sizeof(MyRecords), 1, binaryfile);

besides that you also have wrong sizeof() it shouldn't be sizeof(&MyRec..) it should be sizeof(MyRec..) without &.

Upvotes: 3

Lindydancer
Lindydancer

Reputation: 26094

Hint:

sizeof(&foo)

Is not the same as:

sizeof(foo)

Upvotes: 5

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