Question

我已经阅读了我的C ++书籍中的前50页左右的页面我试图创建一个程序的知识从一个计算一个圆的两个测量，这是什么我想出了：

#include <cstdio>
#include <cstdlib>
#include <iostream>
#include <cmath>
#include <iomanip>

using namespace std;

int main(int nNumberofArgs, char* pszArgs[])
{
    string op;
    int r;
    int a;
    int d;
    int val;

    cout << "This program aims to calculate two measurements of a cicle from one measurement" << endl;
    cout << "Enter the measurement you wish to input from a choice of r, d or a" << endl;
    cin >> op;

    cout << "Please enter the value of this measurement" << endl;
    cin >> val;

    if (op == "r") {
        a = val * val * 3.14;
        d = val * 2;
        r = val;
    }

    if (op == "d") {
        a = val / 2 * val / 2 * 3.14;
        d = val;
        r = val / 2;
    }

    if (op == "a"){
        a = val;
        d = (sqrt(val / 3.14)) * 2;
        r = (sqrt(val / 3.14));
    }

    cout << "The area is " << endl;
    cout << std::setprecision(3) << a << endl;

    cout << "The diameter is  " << endl;
    cout << std::setprecision(3) << d << endl;

    cout << "The radius is " << endl;
    cout << std::setprecision(3) << r << endl;
}

我遇到的问题是我的答案都没有小数，因为你可以看到我试图整合＆＃34; setprecision＆＃34;但它没有奏效。

Answer 1

将int替换为double：

int r;
int a;
int d;
int val;

Answer 2

std::set_precision仅在应用于浮点类型时执行您的预期，例如float或double。我怀疑如果您使用其中一种类型而不是int s

，大多数问题都会得到解决

如何让我的答案显示为小数？

2 个答案: