c-gcc, 103 bytes

Result

AC

Code [DL]

i;a;b;main(){for(;a<50;a++){for(i=0,b=9;b--;)i=i*2|getchar()&1;for(i/=2;i>0;)i-=++b;putchar(i?48:49);}}

stdin

00000000
01111101
11010011
11101100
00000001
11001000
00110111
10111001
10110010
11100111
01101111
10001101
00011100
00010001
10000101
11101000
01001110
11111101
00000110
11001101
01101001
01011011
10111110
11110010
10011001
00001111
10001000
01001101
10101011
00100100
00010101
10110000
11010001
00011111
11011010
00000011
00001111
00001010
10110011
00101101
11010010
10011011
00011100
00110110
01100010
01111010
01000010
10100000
01111000
10000001

stdout

10001010010010001110111011101110000111011010001010

stderr

/tmp/code.c:1:1: warning: data definition has no type or storage class
 i;a;b;main(){for(;a<50;a++){for(i=0,b=9;b--;)i=i*2|getchar()&1;for(i/=2;i>0;)i-=++b;putchar(i?48:49);}}
 ^
/tmp/code.c:1:1: warning: type defaults to ‘int’ in declaration of ‘i’ [-Wimplicit-int]
/tmp/code.c:1:3: warning: data definition has no type or storage class
 i;a;b;main(){for(;a<50;a++){for(i=0,b=9;b--;)i=i*2|getchar()&1;for(i/=2;i>0;)i-=++b;putchar(i?48:49);}}
   ^
/tmp/code.c:1:3: warning: type defaults to ‘int’ in declaration of ‘a’ [-Wimplicit-int]
/tmp/code.c:1:5: warning: data definition has no type or storage class
 i;a;b;main(){for(;a<50;a++){for(i=0,b=9;b--;)i=i*2|getchar()&1;for(i/=2;i>0;)i-=++b;putchar(i?48:49);}}
     ^
/tmp/code.c:1:5: warning: type defaults to ‘int’ in declaration of ‘b’ [-Wimplicit-int]
/tmp/code.c:1:7: warning: return type defaults to ‘int’ [-Wimplicit-int]
 i;a;b;main(){for(;a<50;a++){for(i=0,b=9;b--;)i=i*2|getchar()&1;for(i/=2;i>0;)i-=++b;putchar(i?48:49);}}
       ^
/tmp/code.c: In function ‘main’:
/tmp/code.c:1:52: warning: implicit declaration of function ‘getchar’ [-Wimplicit-function-declaration]
 i;a;b;main(){for(;a<50;a++){for(i=0,b=9;b--;)i=i*2|getchar()&1;for(i/=2;i>0;)i-=++b;putchar(i?48:49);}}
                                                    ^
/tmp/code.c:1:61: warning: suggest parentheses around arithmetic in operand of ‘|’ [-Wparentheses]
 i;a;b;main(){for(;a<50;a++){for(i=0,b=9;b--;)i=i*2|getchar()&1;for(i/=2;i>0;)i-=++b;putchar(i?48:49);}}
                                                             ^
/tmp/code.c:1:85: warning: implicit declaration of function ‘putchar’ [-Wimplicit-function-declaration]
 i;a;b;main(){for(;a<50;a++){for(i=0,b=9;b--;)i=i*2|getchar()&1;for(i/=2;i>0;)i-=++b;putchar(i?48:49);}}
                                                                                     ^

strace