How to write a binary integer to binary file | c

Question

For example: If I had this integer 10101011 I want to write 10101011 to binary file in 1 byte

Somthing like this,I thought but its not working

FILE *f;
int n=10101011;
f=fopen("file","wb");
Fwrite(&n,1,1,f);

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Why you are always does -1 I search and I didnt find something that helped me!!

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Answer 1

Seems that you want to convert a binary to decimal:

#include <stdio.h>

int main(void)
{
    unsigned char c = 0;
    int x = 10101011;
    int rem, i;

    for (i = 0; i < 8; i++) {
        rem = x % 10;
        if (rem == 1) {
            c |= 1U << i;
        }
        x /= 10;
    }
    printf("0x%x\n", c);
    return 0;
}

Output:

0xab

Note that you can't use more than 8 digits for x