Question

我的代码第一次工作，当循环开始时，它停止计算数字！

我希望程序在每次完成计算数字时要求用户选择材料。我用while（1！= 2）{}

#include <iostream>
#include <stdio.h>
#include <math.h>
using namespace std;
float stress, strain, area;
double diameter;
long int F = 9900;
const float pi = 3.141593f;
int i = 0;
int main() {
char meterial;
cout << "This programm calculates the stress and strain of a rod under loads from 10000N to 20000N\n\n";
while (1!=2) 
{
cout << "Choose the meterial of the rod\n\n";
cout << "S For STEEL\nA For ALUMINUM\nC For COPPER\nT For TITANIUM\n\n";
cin >> meterial;

switch (meterial)

{
case 's':
    cout << "\nEnter the diameter of the rod in mm: ";
    cin >> diameter;
    area = (pi * diameter * diameter) / 4;


    while (i <= 50)
    {
        stress = F / area;
        strain = 200 / stress;
        F = F + 100;


        cout << "Load = " << F << "  Stress = " << stress << " N/mm^2" << "  Strain = " << strain << "\n";
        i++;
    }


    break;
case 'a':
    cout << "Enter the diameter of the rod in mm: ";
    cin >> diameter;
    area = (pi * diameter * diameter) / 4;


    while (i <= 50)
    {
        stress = F / area;
        strain = 69 / stress;
        F = F + 100;


        cout << "Load = " << F << "  Stress = " << stress << " N/mm^2" << "  Strain = " << strain << "\n";
        i++;
    }

    break;
case 'c':
    cout << "Enter the diameter of the rod in mm: ";
    cin >> diameter;
    area = (pi * diameter * diameter) / 4;


    while (i <= 50)
    {
        stress = F / area;
        strain = 117 / stress;
        F = F + 100;


        cout << "Load = " << F << "  Stress = " << stress << " N/mm^2" << "  Strain = " << strain << "\n";
        i++;
    }

    break;
case 't':
    cout << "Enter the diameter of the rod in mm: ";
    cin >> diameter;
    area = (pi * diameter * diameter) / 4;


    while (i <= 50)
    {
        stress = F / area;
        strain = 110.3 / stress;
        F = F + 100;


        cout << "Load = " << F << "  Stress = " << stress << " N/mm^2" << "  Strain = " << strain << "\n";
        i++;
    }
    break;
default:
    cout << "You entered a wrong character";
}

}

}

http://i.stack.imgur.com/do3qc.png

Answer 1

在下次通话之前，我没有看到您重置i的值。

但你真的应该在某个函数或方法中循环（while（i <= 50）），除非你已经研究过那些。

Answer 2

变量i永远不会重新初始化为零。如果你更换每个

while (i <= 50)

在switch语句的情况下使用类似的语句

声明

for (int i = 0; i <= 50; ++i)

并删除每个相应块中的i++;行，例如

    case 's':
        cout << "\nEnter the diameter of the rod in mm: ";
        cin >> diameter;
        area = (pi * diameter * diameter) / 4;

        for (int i = 0; i <= 50; ++i) // while (i <= 50) <-- change
        {
            stress = F / area;
            strain = 200 / stress;
            F = F + 100;
            cout << "Load = " << F << "  Stress = " << stress << " N/mm^2" << "  Strain = " << strain << "\n";
            // i++;  <-- remove
        }

您的代码应该按照您的期望进行。您可以考虑将while (1!=2)测试替换为while(1)或for(;;)之类的内容，但这仅仅是因为这些是更常见的习惯用法（您的测试将始终评估为true所以它＆＃39} ; s还是很好。）

开启编辑：还有一件事 - 您永远不会重新初始化 F ，但您需要在计算中对其进行修改。每次执行switch声明时，您都会以 F 的不同初始值开头。

当while循环启动时，代码停止计算并输出数字

2 个答案: