如何重启程序C ++ [英] How to restart the program C++
问题描述
在这里写下您的问题。
任何人都可以告诉我如何在出现ERROR时输入R来重启程序吗？
Write your question here.
can anyone please tell me how to restart the program when i type R if an ERROR appeared ?
#include <conio.h>
#include <iostream>
using namespace std;
void restart() {
/////????
}
int main()
{
float fat, cal = -1, gram = -1 ,R ;
float per;
cout << "Enter the total number of calories" <<" in the food" << endl;
cin >> cal;
cout << "Enter the number of fat grams" <<" in the food" << endl;
cin >> gram;
fat = 9 * gram;
per = (fat / cal) * 100;
if (per > 100 || cal < 0 || fat < 0) {
cout << " \n ( ERROR ,Either the calories or fat grams were incorrect ! ) \n \t To Repeat write [R] then Enter : ";
cin >> R;
restart(); ///// problem _i need to restart the program here <~~~~~~~
}
if (per >= 30)
{
cout << "The percentage of calories" << " from the fat is " << per << "% \n";
}
else
{
cout << "The percentage of calories from" << " the fat is" << fat << "% \n";
cout << "The fat is low in the food";
}
system("pause");
return 0;
}
我的尝试：
void restart（）{
///// ????
}
if（per> 100 || cal< 0 || fat< 0）{
cout<< \ n（错误，卡路里或脂肪克不正确！）\ n \t重复写[R]然后输入：;
cin>> R;
restart（）; /////问题_i需要在这里重启程序< ~~~~~~~
}
不知道是什么要做，我还是新尝试学习c ++
What I have tried:
void restart() {
/////????
}
if (per > 100 || cal < 0 || fat < 0) {
cout << " \n ( ERROR ,Either the calories or fat grams were incorrect ! ) \n \t To Repeat write [R] then Enter : ";
cin >> R;
restart(); ///// problem _i need to restart the program here <~~~~~~~
}
No idea what to do ,im still new on trying to learn c++
推荐答案
你好，
你需要了解在尝试编写甚至正确编译的代码之前，语言的基础知识。
据我所知，如果用户需要再调用cal和gram的方法按下'R'键。我建议编写一个不同的方法，然后在main函数中调用它。
我注意到的一些问题R不应该是一个浮点变量将它定义为字符串或字符。如果用户输入零，那么行
Hello,
You need to understand the basics of the language before trying to write code that even compiles correctly.
From what I understand you need to call the method that takes cal and gram again if the user presses the key 'R'. I would suggest writing a different method that does it and call it in the main function.
Some problems I noticed R should not be a floating point variable define it as a string or char. Also the line
per = (fat / cal) * 100;将抛出除零异常。
对于你的问题来说，写一个递归函数就可以了。
will throw divide by zero exception if the user inputs zero.
A for your problem, writing a recursive function will do the trick.
int main()
{
Calculate();
}
private void Calculate()
{
float fat, cal = -1, gram = -1;
char R;
float per;
cout << "Enter the total number of calories" <<" in the food" << endl;
cin >> cal;
cout << "Enter the number of fat grams" <<" in the food" << endl;
cin >> gram;
fat = 9 * gram;
if(cal!= 0)
{
per = (fat / cal) * 100;
}
if (per > 100 || cal < 0 || fat < 0)
{
cout << " \n ( ERROR ,Either the calories or fat grams were incorrect ! ) \n \t To Repeat write [R] then Enter : ";
cin >> R;
if(R == 'R' || R == 'r')
{
Calculate(); //Calls the method all over again if the user inputs R.
}
}
if (per >= 30)
{
cout << "The percentage of calories" << " from the fat is " << per << "% \n";
}
else
{
cout << "The percentage of calories from" << " the fat is" << fat << "% \n";
cout << "The fat is low in the food";
}
}
无需重启应用程序。只需使用while循环：
There is no need to restart the application. Just use a while loop:
bool bRedo = false;
do
{
cout << "Enter the total number of calories" <<" in the food" << endl;
cin >> cal;
cout << "Enter the number of fat grams" <<" in the food" << endl;
cin >> gram;
fat = 9 * gram;
// Zero cal is an error too and would result in a division by zero
// Therefore it must be checked before performing the division
if (cal <= 0 || fat < 0 || fat / cal > 1)
{
cout << " \n ( ERROR ,Either the calories or fat grams were incorrect ! ) \n \t To Repeat write [R] then Enter : ";
string strRestart;
getline(cin, strRestart);
if (0 == strRestart.compare("R"))
bRedo = true;
else
return 1;
}
else
per = (fat / cal) * 100;
}
while (bRedo);
非常感谢！ ，感谢你的帮助。
Thanks a lot guys ! ,appreciate your help all .
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