精通C的大虾们,加进来看看...

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精通C的大虾们,加进来看看...10

如何用C预言来实现，把IP地址的点表示法转换成一个无符号整数；（ex：172.17.72.1=》172被存放在高8位，1被放在低8位）（要求不能使用库函数）

感谢你们的帮助........

问题补充：<div class="quote_title">王者之剑写道</div><div class="quote_div">#include <stdio.h> unsigned int int_ip_addr(const char* pip) {   unsigned int ret = 0;   unsigned int byte = 0;   int byte_count = 0 ;   int digit_count = 0;   while(*pip != '\0'){     /* 非法字符 */     if(*pip !='.' && (*pip <'0' || *pip >'9')){        return 0;     }     if(*pip == '.'){       byte_count++;       /*'.'前没有数字或者这一小节的数字值过大或者'.'过多*/       if(digit_count == 0 || byte > 255 || byte_count>3){          return 0;       }       ret = (ret<<8)|byte;       byte = 0;       digit_count = 0;     }else{       digit_count++;       /*数字个数过多*/       if(digit_count>3 ){         return 0;       }       byte *= 10;       byte += *pip-'0';     }     pip++;   }   return (ret<<8)|byte; } void my_print(char* pip, unsigned int ip) {   printf("str ip: %s\n", pip);   printf("int ip: %u ", ip);   printf("convert to str: %d.", (ip&0xff000000)>>24);   printf("%d.", (ip&0x00ff0000)>>16);   printf("%d.", (ip&0x0000ff00)>>8);   printf("%d\n", (ip&0x000000ff)); } int main(void) {   int i;   char* pip[11] = {"172.1236.55.32",".36.55.32","172.y4.55.32",                  "192...","192.168.10.12", "192.168.10.0.",                  "255.255.255.255","192.ab1.0.0", "192.168..255",                  "192168016600999999","255.355.2.254"};   for(i=0;i<11;i++){     my_print(pip[i], int_ip_addr(pip[i]));   }   } </div> 能不能注释多一点呢....我新手吖,哈哈``` 解释清楚一点呐``` 准备给分你哦..

2010年1月16日 20:16

didon163
20
0 0 0

2个答案按时间排序按投票排序

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#include <stdio.h>

unsigned int int_ip_addr(const char* pip)
{
unsigned int ret = 0;
unsigned int byte = 0;
int byte_count = 0 ;
int digit_count = 0;
while(*pip != '\0'){
 /* 非法字符 */
 if(*pip !='.' && (*pip <'0' || *pip >'9')){
 return 0;
 }
 if(*pip == '.'){
 byte_count++;
 /*'.'前没有数字或者这一小节的数字值过大或者'.'过多*/
 if(digit_count == 0 || byte > 255 || byte_count>3){
 return 0;
 }
 ret = (ret<<8)|byte;
 byte = 0;
 digit_count = 0;
 }else{
 digit_count++;
 /*数字个数过多*/
 if(digit_count>3 ){
 return 0;
 }
 byte *= 10;
 byte += *pip-'0';
 }
 pip++;
}
return (ret<<8)|byte;
}

void my_print(char* pip, unsigned int ip)
{
printf("str ip: %s\n", pip);
printf("int ip: %u ", ip);
printf("convert to str: %d.", (ip&0xff000000)>>24);
printf("%d.", (ip&0x00ff0000)>>16);
printf("%d.", (ip&0x0000ff00)>>8);
printf("%d\n", (ip&0x000000ff));
}
int main(void)
{
int i;
char* pip[11] = {"172.1236.55.32",".36.55.32","172.y4.55.32",
 "192...","192.168.10.12", "192.168.10.0.",
 "255.255.255.255","192.ab1.0.0", "192.168..255",
 "192168016600999999","255.355.2.254"};
for(i=0;i<11;i++){
 my_print(pip[i], int_ip_addr(pip[i]));
}

}

2010年1月17日 18:55

王者之剑
161
0 0 0

添加评论

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unsigned long get_ip_addr(char *pip)
{
 int i = 0,k = 0;
 unsigned char c_tmp;
 unsigned long l_tmp = 0;
 unsigned long r_ip = 0;

 while('\0' != *pip)
 {
 c_tmp = *pip++;
 if('.' == c_tmp)
 {
 if(++k <= 3)
 {
 r_ip |= l_tmp;
 r_ip <<= 8;
 i = 0;
 l_tmp = 0;
 }
 else
 {
 return(0); // 错误 IP
 }
 }
 else if(++i < 4)
 {
 l_tmp *= 10;
 l_tmp += (c_tmp - '0');
 }
 else
 {
 return(0); // 错误 IP
 }
 }
 r_ip |= l_tmp;
 return(r_ip);
}