bitwise operation in c about mask - c

Question

Here is the question, write a produre
void compress(char *str, char mask)
that compress the string according to the specified 8- bit mask. for example, if str is
The quick red fox jumped
and the binary representation of mask is
10110011
the resulting value of str would be
Th ickrefoxjued
This result is determined by duplicating the mask for every group of eight characters and eliminating characters masked by a 0 bit:
The quick red fox jumped
101100111011001110110011
Note: the string being compress might bot be a multiple of eight characters in length, as it is in this example.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void compress(char *, unsigned char);
int main()
{
unsigned char mask = 179;
char *str;
str = malloc(100 * sizeof(char));
scanf("%s", str);
compress(str, mask);
return 0;
}
void compress(char *str, unsigned char mask)
{
float len = strlen(str);
int times;
if (len / 8 > (int)(len / 8))
{
times = (int)(len / 8 + 1);
}
for (int i = 0; i < times; i++)
{
mask = mask << 8 | 0263;
}
unsigned bit = 1u << (8 * times);
for (char *p = str; *p; p++)
{
for ( ; bit ; bit >>= 1)
{
if ((bit & mask) > 0)
{
printf("%c", *p);
}
}
}
}
This is my code, I the output is not what I want, can someone help thx.

Answer 1

This will fix your issue (change compress function as follow):
#include <iostream>
#include <string.h>
void compress(char *str, unsigned char mask)
{
// And as others said You can avoid using strlen
//int len = strlen(str);
//for(int i=0;i<len;i++)
for(int i=0;str[i];i++)
{
if(((mask >> (7 - (i%8))) & 0x01))
printf("%c", str[i] );
}
}
int main()
{
unsigned char mask = 179;
char *str;
str = (char*)malloc(100 * sizeof(char));
fgets(str, 100,stdin);
compress(str, mask);
return 0;
}
I've used fgets instead of scanf because scanf does not read space.
The quick red fox jumped
Te ickrefoxjued