下面的程序已经完成“从键盘上读取4个字符,把它们放在一个四字节的整型变量中,把这个变量的值显示为十六进制”
后半部分你自己按照下面的思路动动脑筋吧!
#include <iostream.h>
#include <iomanip.h>
int main()
{
char cKey1='\0',cKey2='\0',cKey3='\0',cKey4='\0';
unsigned int iKey=0,iKey1=0,iKey2=0,iKey3=0,iKey4=0;//一定要注意是无符号整型
cin>>cKey1>>cKey2>>cKey3>>cKey4;

iKey1=int(cKey1);
iKey1<<=24; //移位操作实现

iKey2=int(cKey2);
iKey2<<=16;

iKey3=int(cKey3);
iKey3<<=8;

iKey4=int(cKey4);

iKey=iKey1+iKey2+iKey3+iKey4;

cout<<hex<<iKey<<endl;

return 0;
}