2009-10-19c语言日记（位操作）

/*使用位操作符来显示二进制*/#include<stdio.h>char *itobs(int n, char *ps);void show_bstr(const char *);int invert_end(int num, int bits);int main(void){char bin_str[8 * sizeof(int) + 1];int number;puts("Enter intrgers and them in binary.");puts("Non-numberic input terminates program.");while(scanf("%d",&number) == 1){itobs(number,bin_str);printf("%d is/n",number);show_bstr(bin_str);putchar('/n');number = invert_end(number, 4);printf("Inverting the last 4 bits gives/n");show_bstr(itobs(number,bin_str));putchar('/n');}puts("Bye!");return 0;}char *itobs(int n, char *ps){int i;static int size = 8 * sizeof(int);for(i = size - 1; i >= 0; i--,n >>= 1){ps[i] = (01 & n) + '0';}ps[size] = '/0';return ps;}void show_bstr(const char * str){int i = 0;while(str[i]){putchar(str[i]);if(++i % 4 == 0 && str[i]){putchar(' ');}}}int invert_end(int num, int bits){int mask = 0;int bitval = 1;while(bits-- > 0){mask |= bitval;bitval <<= 1;}return num^mask;}

/*位字段*/#include<stdio.h>/*是否透明和是否可见*/#define YES 1#define NO 0/*边框线的样式*/#define SOLID 0#define DOTTED 1#define DASHED 2/*三原色*/#define BLUE 4#define GREEN 2#define RED 1/*混合颜色*/#define BLACK 0#define YELLOW (RED|GREEN)#define MAGENTA (RED|BLUE)#define CYAN (GREEN|BLUE)#define WHITE (RED|BLUE|GREEN)const char * colors[8] = {"black","red","green","YELLOW","blue","magenta","cyan","white"};struct box_props{unsigned int opaque :1;unsigned int fill_color :3;unsigned int :4;unsigned int show_border :1;unsigned int border_color:3;unsigned int border_style:2;unsigned int :2;};void show_settings(const struct box_props *pb);int main(void){struct box_props box = {YES, YELLOW, YES, GREEN, DASHED};printf("Original box settings:/n");show_settings(&box);box.opaque = NO;box.fill_color = WHITE;box.border_color = MAGENTA;box.border_style = SOLID;printf("/nModified box settings:/n");show_settings(&box);return 0;}void show_settings(const struct box_props *pb){printf("Box is %s /n",pb->opaque == YES? "opaque": "transparent");printf("The fill color is %s./n",colors[pb->fill_color]);printf("Border %s ./n",pb->show_border == YES? "shown": "not shown");printf("The border color is %s./n",colors[pb->border_color]);printf("The border style is ");switch(pb->border_style){case SOLID : printf("solid./n"); break;case DOTTED: printf("dotted/n"); break;case DASHED: printf("dashed/n"); break;default : printf("unknown type./n"); break;}}

 

#include<stdio.h>#include<stdlib.h>#include<math.h>int itob(char * ps);int main(void){char pbin[20];puts("请输入二进制数/n");gets(pbin);printf("十进制数为%d/n",itob(pbin));return 0;}int itob(char * ps){int count,b;int sum = 0;for(count = strlen(ps) - 1;count >= 0;count--){b = *(ps++) -48;sum = sum + b * (pow((double)2,count));}return sum;}

 

#include<stdio.h>#include<math.h>#include<stdlib.h>int btoi(char *str);char *itos(int n);int main(int argc,char *argv[]){int a,b;int a_1,b_1,anb,a_b,aob;char bstr[8* sizeof (int) + 1];if(argc != 3){printf("请使用2个命令行参数(二进制数）./n");exit(1);}a = btoi(argv[1]);b = btoi(argv[2]); a_1 = ~a;b_1 = ~b;anb = a & b;a_b = a | b;aob = a ^ b;printf("~a is %s/n",itos(a_1,bstr)); printf("~b is %s/n",itos(b_1,bstr));printf("a&b is %s/n",itos(anb,bstr));printf("a|b is %s/n",itos(a_b,bstr));printf("a^b is %s/n",itos(aob,bstr));return 0;}int btoi(char * str){int val = 0;while (*str != '/0') { val = 2 * val + (*str++ - '0');/*mark*/ } return val;}char *itos(int n,char *ps){static int size = 8 * sizeof(int);int count;for(count = size - 1; count >= 0; count--, n>>=1){ps[count] = (01 & n) + '0';}ps[size] = '/0';/*mark*/return ps;}