displays binary... useing in another program

readoutbits.c

#include<stdio.h>

char testbit[] = {0x7e,0xff};
unsigned char teststring[] = "THIS IS SO COOL";

void leftShift(unsigned char*, long unsigned int);
void displayBits(char*, int);

void leftShift(unsigned char *array, long unsigned int length){ //this function works

  array[0] = (array[0]) << 1;

  if(length == sizeof(unsigned char)){
    return;
  }

  int i;
  unsigned char tmpbit;
  for(i = 0; i < (length-1); i++){
    tmpbit = (array[i+1] & 0x80);
    tmpbit >>= 7;
    array[i] |= tmpbit;
    array[i+1] = (array[i+1]) << 1;
  }
  array[length] = array[length] << 1;
}    
    

void displayBits(char* whatever,int length){  // this one stops after 8bytes
  printf("\n\n%d\n\n", length);
  int i;
  for(i = 0; i < length; i++){
    printf("%d", ((whatever[0] >> 7)&1));
    leftShift(&whatever[0], sizeof(whatever));
  }
}

int main(char argc[], char *argv[]){
  displayBits(&teststring[0], sizeof(teststring)*8);
  printf("\n");
  return 0;
}