UTF8转整数问题

DAVID9785 2016-09-12 02:51:31

"A"这个字，在UTF8为一字节编码
16进位表示法为：41
10进位表示法为：65

"您"这个字，在UTF8为三字节编码
16进位表示法为：E6 82 A8
10进位表示法为：230 130 168

UTF8.txt内容为：您 \n A
我现在想将UTF8.txt内容转化成10进位表示法

#include <stdlib.h>
#include <fstream>
#include <iostream>
#include <cstdlib>
using namespace std;
int main(void)
{
int x;int y;
char txt[80]="";

ifstream ifile("C:\\Users\\Gon\\Desktop\\UTF8.txt",ios::binary);
if(ifile.is_open())
{
while(!ifile.eof())
{
ifile >> txt;
cout << txt<< endl;

x=char (txt[0]);
switch(x)
{ case 0-127:
cout <<"1st byte~ " <<x << endl;
break;
case 240-247:
cout <<"1st byte~ " <<x << endl;
y=char (txt[1]);
cout <<"2nd byte~ " <<y << endl;
y=char (txt[2]);
cout <<"3rd byte~ " <<y << endl;
break;
default:
cout <<"1st byte~ " <<x << endl;
y=char (txt[1]);
cout <<"2nd byte~ " <<y << endl;
y=char (txt[2]);
cout << "3rd byte~ " <<y << endl;
y=char (txt[3]);
cout << "4th byte~ " <<y << endl;
y=char (txt[4]);
cout << "5th byte~ " <<y << endl;
y=char (txt[5]);
cout << "6th byte~ " <<y << endl;
}

}
}
else
cout << "fail to open file" << endl;
ifile.close(); // close file
system("pause");
return 0;
}

我想要得到的结果是：
您
1st byte~ 230
2nd byte~ 130
3rd byte~ 168
A
1st byte~ 65

可是实际跑出来的结果是：
您
1st byte~ -26
2nd byte~ -126
3rd byte~ -88
4th byte~ 0
5th byte~ 0
6th byte~ 0
A
1st byte~ 65
2nd byte~ 0
3rd byte~ -88
4th byte~ 0
5th byte~ 0
6th byte~ 0

几个问题点：
１．　A的1st byte是65 应该代入case 0-127 可是实际上却代入default case 请问为何？
２．　"A"跑出来是单字节　数值65没错　"您"跑出来是三个字节　数值完全不对而且还是负数请问该如何修改？

感谢您的细心阅帖,谢谢!!

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