题目：
思路：
先将十六进制数转换成二进制数，再由二进制数转换成八进制
注意当不满位的时候，首部添加0
代码：
1 #include<bits/stdc++.h> 2 using namespace std; 3 int main() 4 { 5 int n; 6 scanf("%d ",&n); 7 while(n--) 8 { 9 string s1,s2; 10 getline(cin,s1); 11 for(int i=0;s1[i]!=' ';i++) 12 { 13 switch(s1[i]) 14 { 15 case '0': s2+="0000";break; 16 case '1': s2+="0001";break; 17 case '2': s2+="0010";break; 18 case '3': s2+="0011";break; 19 case '4': s2+="0100";break; 20 case '5': s2+="0101";break; 21 case '6': s2+="0110";break; 22 case '7': s2+="0111";break; 23 case '8': s2+="1000";break; 24 case '9': s2+="1001";break; 25 case 'A': s2+="1010";break; 26 case 'B': s2+="1011";break; 27 case 'C': s2+="1100";break; 28 case 'D': s2+="1101";break; 29 case 'E': s2+="1110";break; 30 case 'F': s2+="1111";break; 31 } 32 } 33 while(s2.size()%3!=0) 34 { 35 s2 = "0"+s2; 36 } 37 int i=0; 38 while(i<s2.size()&&(s2[i]-'0')*4+(s2[i+1]-'0')*2+(s2[i+2]-'0')==0) i+=3; 39 if(i==s2.size()) cout<<"0"; 40 else 41 { 42 for(;i<s2.size();i+=3) 43 { 44 printf("%d",(s2[i]-'0')*4+(s2[i+1]-'0')*2+(s2[i+2]-'0')); 45 } 46 } 47 cout<<endl; 48 } 49 return 0; 50 }