类型强制转换问题

[Tails136]

#include "iostream.h"
void main()
{
float fDecpounds=0;
float fDecfrac=0;
int nPounds=0,nShillings=0,nPence=0;

cout<<"Enter decimal pounds: ";
cin>>fDecpounds;

nPounds = (int)(fDecpounds);

fDecfrac = fDecpounds-nPounds;
nShillings = (int)(fDecfrac*20);

fDecfrac = fDecfrac*20-nShillings;
nPence = (int)(fDecfrac*12);

cout<<"Equivalent in old notation: ￡"<<nPounds<<"."<<nShillings<<"."<<nPence<<endl;
}
代码如上，
问题：输入3.8
nShillings的值按道理是16，但输出15
我跟踪来一下问题出在 nShillings = (int)(fDecfrac*20);
fDecfrac的值为0.8，但(int)(fDecfrac*20); 值却是15？？？？
为什么，要怎么真确输出呢？

[Baocai3000]

//============================================================================
// Name        : cast.cpp
// Author      :
// Version     :
// Copyright   : Your copyright notice
// Description : Hello World in C++, Ansi-style
//============================================================================

#include <iostream>
using namespace std;

int main() {
	float fDecpounds = 0;
	float fDecfrac = 0;
	int nPounds = 0, nShillings = 0, nPence = 0;

	cout << "Enter decimal pounds: ";
	cin >> fDecpounds;

	nPounds = (int) (fDecpounds);

	fDecfrac = fDecpounds - nPounds;
	nShillings = (int) (fDecfrac * 20);

	fDecfrac = fDecfrac * 20 - nShillings;
	nPence = (int) (fDecfrac * 12);

	cout << "Equivalent in old notation: ￡" << nPounds << "." << nShillings
			<< "." << nPence << endl;
	return 0;
}

Result:

Enter decimal pounds: 0.8
Equivalent in old notation: ￡0.16.0

[diamond1983]

int main() {
    float fDecpounds = 0;
    float fDecfrac = 0;
    int nPounds = 0, nShillings = 0, nPence = 0;

    cout << "Enter decimal pounds: ";
    cin >> fDecpounds;

    nPounds = (int) (fDecpounds);

    fDecfrac = fDecpounds - nPounds;
    nShillings = (int) (fDecfrac * 20);

    fDecfrac = fDecfrac * 20 - nShillings;
    nPence = (int) (fDecfrac * 12);

    cout << "Equivalent in old notation: ￡" << nPounds << "." << nShillings
            << "." << nPence << endl;
    return 0;

[giant1st]

把nShillings换成Float 就可以了，
Float 到 int 的转换 会丢失数据的。

[Tails136]

2楼3楼的为什么把我的代码重打了一边，输入3.8问题依旧存在
4楼的谢谢，要求必须是存在int型中的，而且我要获得整数位，有用，又解决方法吗？

[dzc8866]

有点难搞噢，等待高手解决，请高手顺便讲讲float、int怎么存储，强制转换时候怎么截取；Up!

[koo8]

搂主，你输入0.8，4.8，5.8...10.8等都能出来16。唯独输入1.8，2.8，3.8就得15，晕啦！！！

这个问题确实很奇怪，期待高手解决。