如何在c中打印位
我正在写一个函数来打印c中的位，我只允许使用write函数。 我的function对其他数字不起作用。
void print_bits(unsigned char octet) { int oct; int div; div = 128; oct = octet; while (!(div <= 1)) { if (div <= oct) { write(1, "1", 1); oct = oct % div; } else { write(1, "0", 1); div = div / 2; } } }
实时代码
我重写了代码是否有printf转换器以二进制格式打印？
void print_bits(unsigned char octet) { int z = 128, oct = octet; while (z > 0) { if (oct & z) write(1, "1", 1); else write(1, "0", 1); z >>= 1; } }
包括CHAR_BIT limits.h ，允许您概括函数以允许传递任何长度的值，但将输出限制为所需的字节数。 传递文件描述符将允许写入任何打开的描述符（或者只是传递STDOUT_FILENO来写入stdout 。
void writebits (const unsigned long v, int fd) { if (!v) { putchar ('0'); return; }; size_t sz = sizeof v * CHAR_BIT; unsigned long rem = 0; while (sz--) if ((rem = v >> sz)) write (fd, (rem & 1) ? "1" : "0", 1); }
例如：
#include #include /* CHAR_BIT */ #ifndef CHAR_BIT # define CHAR_BIT 8 #endif void writebits (const unsigned long v, int fd) { if (!v) { putchar ('0'); return; }; size_t sz = sizeof v * CHAR_BIT; unsigned long rem = 0; while (sz--) if ((rem = v >> sz)) write (fd, (rem & 1) ? "1" : "0", 1); } int main (void) { unsigned v = 0xcafebabe; writebits (v, STDOUT_FILENO); putchar ('\n'); writebits ((unsigned char)(v >> 24), STDOUT_FILENO); putchar ('\n'); return 0; }
示例输出
$ ./bin/writebits 11001010111111101011101010111110 11001010
如果你想打印位然后使用按位运算符，你可以这样做……
这样的例子：
for(i=31 ; i>=0 ; i--) { if(num & 1<< i) /* num & 1 << position printf("1 "); else printf("0 "); } printf("\n");
在互联网上找到的地方：
void printBits( void const * const ptr, size_t const size ) { printf( "hexVal = %#08x; decVal = %i \n", * ( uint* )ptr, * ( uint* )ptr ); unsigned char *b = ( unsigned char* ) ptr; unsigned char byte; int i, j; for (i=size-1;i>=0;i--) for (j=7;j>=0;j--) { byte = (b[i] >> j) & 1; printf( " %u ", byte ); } puts(""); for( int ind = 31; ind > 9; ind-- ) printf( "%d ", ind ); for( int ind = 9; ind > -1; ind-- ) printf( " %d ", ind ); puts(""); puts(""); }; void compareValsBits( const void * ptrA, size_t sizeA, const void * ptrB, size_t sizeB ) { if ( sizeA != sizeB ) return; printf( "comparing: \n[%#08x](%i)\n[%#08x](%i)\n====\n", * ( uint* )ptrA, * ( uint* )ptrA, * ( uint* )ptrB, * ( uint* )ptrB ); unsigned char *a = ( unsigned char* ) ptrA; unsigned char *b = ( unsigned char* ) ptrB; unsigned char byteA, byteB; int i, j; for (i=sizeA-1;i>=0;i--) for (j=7;j>=0;j--) { byteA = (a[i] >> j) & 1; printf( " %u ", byteA ); } puts(""); for (i=sizeA-1;i>=0;i--) for (j=7;j>=0;j--) { byteB = (b[i] >> j) & 1; printf( " %u ", byteB ); } puts(""); for( int ind = 31; ind > 9; ind-- ) printf( "%d ", ind ); for( int ind = 9; ind > -1; ind-- ) printf( " %d ", ind ); puts(""); for (i=sizeA-1;i>=0;i--) for (j=7;j>=0;j--) { byteA = (a[i] >> j) & 1; byteB = (b[i] >> j) & 1; if ( byteA == byteB ) printf( " " ); else printf( " x " ); } printf( "\n====\n" ); };
一些简单的宏展开设置和重置位： https ： //stackoverflow.com/questions/1872220/is-it-possible-to-iterate-over-arguments-in-variadic-macros
#include typedef __uint32_t uint; //============================================================================================== #define STRINGIZE(arg) #arg #define CONCATENATE(arg1, arg2) arg1##arg2 #define FOR_EACH_1(macroName, param, x, ...) macroName(param, x) #define FOR_EACH_2(macroName, param, x, ...) macroName(param, x); FOR_EACH_1(macroName, param, __VA_ARGS__); #define FOR_EACH_3(macroName, param, x, ...) macroName(param, x); FOR_EACH_2(macroName, param, __VA_ARGS__); #define FOR_EACH_4(macroName, param, x, ...) macroName(param, x); FOR_EACH_3(macroName, param, __VA_ARGS__); #define FOR_EACH_5(macroName, param, x, ...) macroName(param, x); FOR_EACH_4(macroName, param, __VA_ARGS__); #define FOR_EACH_6(macroName, param, x, ...) macroName(param, x); FOR_EACH_5(macroName, param, __VA_ARGS__); #define FOR_EACH_7(macroName, param, x, ...) macroName(param, x); FOR_EACH_6(macroName, param, __VA_ARGS__); #define FOR_EACH_8(macroName, param, x, ...) macroName(param, x); FOR_EACH_7(macroName, param, __VA_ARGS__); #define FOR_EACH_NARG(...) FOR_EACH_NARG_(__VA_ARGS__, FOR_EACH_RSEQ_N()) #define FOR_EACH_NARG_(...) FOR_EACH_ARG_N(__VA_ARGS__) #define FOR_EACH_ARG_N(_1, _2, _3, _4, _5, _6, _7, _8, N, ...) N #define FOR_EACH_RSEQ_N() 8, 7, 6, 5, 4, 3, 2, 1, 0 #define FOR_EACH_(N, macroName, param, x, ...) CONCATENATE(FOR_EACH_, N)(macroName, param, x, __VA_ARGS__) #define FOR_EACH(macroName, param, x, ...) FOR_EACH_(FOR_EACH_NARG(x, __VA_ARGS__), macroName, param, x, __VA_ARGS__) //============================================================================================ //-------------------------------------------------------------------------------------------- //------------------------ MACRO KERNELS ---------------------------------------------------- //-------------------------------------------------------------------------------------------- #define SET_BIT( VARIABLE, bitNo ) { VARIABLE = ( ( ( VARIABLE >> bitNo ) & 0x1u ) != 0x1u ) \ ? VARIABLE |= 0x1u << bitNo \ : VARIABLE = VARIABLE; \ } #define RESET_BIT( VARIABLE, bitNo ) { VARIABLE = ( ( ( VARIABLE >> bitNo ) & 0x1u ) != 0x0u ) \ ? VARIABLE &= ~( 0x1u << bitNo ) \ : VARIABLE = VARIABLE; \ } #define BIT_VAL( VARIABLE, bitNo ) ( VARIABLE >> bitNo ) & 0x1u //-------------------------------------------------------------------------------------------- //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% uint a = 0x0u; int main( void ) { FOR_EACH( SET_BIT, a, 0, 1, 2 ); printf( "0x%.8X\n", a ); FOR_EACH( RESET_BIT, a, 1, 2 ); printf( "0x%.8X\n", a ); return 0; };//end of main() //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
#include int countOne =0; int countZero =0; void print_bits(int n,unsigned int num) { if(n == 31) return; print_bits(n+1,num); (num & (1<