bit.c

#include<stdio.h>

int i;
char c;
FILE *f;
int main() {

f = fopen("b.txt","rb");

while ((i = fread(&c,1,1,f)) > 0)
{
// printf("%d\n", i);

    char b;

/*
    b = c >> 7;
    b = ~b;
    b = b << 7;
    c = c & 0b01111111 | b;
*/
    c = ~c;
    printf( "%c", c);
}

}