python/C++专题课程/基础知识/十六进制转八进制.cpp

#include<bits/stdc++.h>
using namespace std;
int main() {
	int n = 0, i = 0, j = 0, temp = 0, nNum = 0;
	char ch;
	string strHex[10];
	string strBin[10];
	string strOct[10];

	cin>>n;
	for (i = 0; i < n; ++i) {
		cin>>strHex[i];
	}

	//十六进制转二进制
	for (i = 0; i < n; ++i) {
		j = 0;
		while (strHex[i][j]) {
			switch(strHex[i][j]) {
				case '0':
					strBin[i] += "0000";
					break;
				case '1':
					strBin[i] += "0001";
					break;
				case '2':
					strBin[i] += "0010";
					break;
				case '3':
					strBin[i] += "0011";
					break;
				case '4':
					strBin[i] += "0100";
					break;
				case '5':
					strBin[i] += "0101";
					break;
				case '6':
					strBin[i] += "0110";
					break;
				case '7':
					strBin[i] += "0111";
					break;
				case '8':
					strBin[i] += "1000";
					break;
				case '9':
					strBin[i] += "1001";
					break;
				case 'A':
					strBin[i] += "1010";
					break;
				case 'B':
					strBin[i] += "1011";
					break;
				case 'C':
					strBin[i] += "1100";
					break;
				case 'D':
					strBin[i] += "1101";
					break;
				case 'E':
					strBin[i] += "1110";
					break;
				case 'F':
					strBin[i] += "1111";
					break;
				default:
					break;
			}
			++j;
		}
	}

	//二进制转化为八进制
	for (i = 0; i < n; ++i) {
		j = strBin[i].size()-1;//获得长度
		while (strBin[i][j] && j>=0) {
			temp = 3;
			nNum = 0;
			while (temp-- && j>=0) {
				if ('1' == strBin[i][j]) {
					switch(temp) {
						case 0:
							nNum += 4;
							break;
						case 1:
							nNum += 2;
							break;
						case 2:
							nNum += 1;
							break;
						default:
							break;
					}
				}
				--j;
			}
			strOct[i] += (nNum+'0');
		}
	}

	//字符串逆序
	for (i = 0; i < n; ++i) {
		temp = strOct[i].size()-1;
		for (j = 0; j <= temp/2; ++j) {
			ch = strOct[i][j];
			strOct[i][j] = strOct[i][temp-j];
			strOct[i][temp-j] = ch;
		}
	}
	//打印
	for (i = 0; i < n; ++i) {
		j = 0;
		while (strOct[i][j++] == '0');//跳过前面的0
		for(--j; j < strOct[i].size(); ++j) {
			cout<<strOct[i][j]-'0';
		}
		/*if (i != n-1)*/
		cout<<endl;
	}
	return 0;
}