学步园

临时保存，回头测试

//判断一个IP地址是否合法，耗时2h<br /> void main(void)<br /> {<br /> char s[16];<br /> memset(s,'/0',16);<br /> int IP[5]={0,0,0,0};<br /> int i=0,j=0,count=0;<br /> cout<<"Please input an IP address/n";<br /> cin>>s;<br /> int StrLenth=strlen(s);//15</p> <p> //cout<<StrLenth<<endl;</p> <p> if(StrLenth>15)<br /> {//长度最大为15<br /> cout<<"Invalid address/n";<br /> exit(0);<br /> }</p> <p> else<br /> {<br /> for(i=0;i<StrLenth;i++)<br /> {<br /> if (((s[i]>'0'&&s[i]<'9')||(s[i]=='.'))&&!strstr(s,".."))//都是数字或者点号,而且没有连点<br /> {<br /> //转换为数值<br /> if(s[i]=='.')<br /> {<br /> count++;<br /> j++;<br /> }<br /> else<br /> IP[j]=IP[j]*10+(s[i]-'0');<br /> }<br /> else<br /> {<br /> cout<<"Invalid address/n";<br /> exit(0);<br /> }<br /> }<br /> if (count>3)<br /> {//分段太多<br /> cout<<"Invalid address/n";<br /> exit(0);<br /> }<br /> //cout<<IP[0]<<'.'<<IP[1]<<'.'<<IP[2]<<'.'<<IP[3]<<endl;</p> <p> for (j=0;j<4;j++ )<br /> {//判断取值范围<br /> if(IP[j]>255)<br /> {<br /> cout<<"Invalid address/n";<br /> exit(0);<br /> }<br /> }<br /> cout<<"Valid address/n";<br /> }<br /> }