c-gcc, 41 bytes

Result

WA

Code [DL]

main(a,b){b=16;a=sqrt(b);printf("%d",a);}

stdin

01011011
00000110
10100100
00110000
01110000
01000110
00001111
10010110
01001110
01001001
00010111
10100001
00110111
10111110
01110111
10101011
00001010
00110100
00010101
10001000
10001010
00100100
10000100
01011100
00011100
01100110
10110101
10101011
10011001
10011001
11101011
00000000
00100111
11111011
11010010
01111000
00101101
00000011
01101111
11100111
01010000
11111101
10011111
01100000
01000010
00000001
00010110
01101001
10101001
01011110

stdout

4

stderr

/tmp/code.c:1:1: warning: return type defaults to ‘int’ [-Wimplicit-int]
 main(a,b){b=16;a=sqrt(b);printf("%d",a);}
 ^
/tmp/code.c: In function ‘main’:
/tmp/code.c:1:1: warning: type of ‘a’ defaults to ‘int’ [-Wimplicit-int]
/tmp/code.c:1:1: warning: type of ‘b’ defaults to ‘int’ [-Wimplicit-int]
/tmp/code.c:1:18: warning: implicit declaration of function ‘sqrt’ [-Wimplicit-function-declaration]
 main(a,b){b=16;a=sqrt(b);printf("%d",a);}
                  ^
/tmp/code.c:1:18: warning: incompatible implicit declaration of built-in function ‘sqrt’
/tmp/code.c:1:18: note: include ‘<math.h>’ or provide a declaration of ‘sqrt’
/tmp/code.c:1:26: warning: implicit declaration of function ‘printf’ [-Wimplicit-function-declaration]
 main(a,b){b=16;a=sqrt(b);printf("%d",a);}
                          ^
/tmp/code.c:1:26: warning: incompatible implicit declaration of built-in function ‘printf’
/tmp/code.c:1:26: note: include ‘<stdio.h>’ or provide a declaration of ‘printf’

strace