乘以双精度类型值会在输出中给出随机/垃圾答案

发布于 2025-01-02 17:59:35 字数 655 浏览 4 评论 0原文

#include <iostream>
#include <string>
using namespace std;

int main() {

double age;
double months;
string name;

months = age*12.0;

cout << "Enter your name and age: ";
cin >> name >> age;
cout << "Hello " << name << " age " << age << " (" << months << " months)\n";

return(0);
}

该程序要求输入姓名和年龄，并且应将姓名和年龄放在句子中，并将年龄以月为单位放在括号中。输出给出类似： Hello Bob 年龄 20（1.82561e-313 个月），但应该是 Hello Bob 年龄 20（240 个月）。我没有使用 int，因为我希望能够输入年龄的非 int 值。我尝试过 12 而不是 12.0，并尝试声明一个变量并执行 Months = Age*m 其中 m = 12.0 但结果是相同的。顺便说一句，无论年龄变量是什么，随机值都大致相同。为什么会发生这种情况？另外，这会是链接时错误还是运行时错误？

原文

#include <iostream>
#include <string>
using namespace std;

int main() {

double age;
double months;
string name;

months = age*12.0;

cout << "Enter your name and age: ";
cin >> name >> age;
cout << "Hello " << name << " age " << age << " (" << months << " months)\n";

return(0);
}

The program asks for name and age, and should out put the name and age in a sentence with the age in months in parentheses.
Output gives something like:
Hello Bob age 20 (1.82561e-313 months), but should be Hello Bob age 20 (240 months). I did not use int because I wanted to be able to input non int values for age.
I have tried 12 instead of 12.0 and tried declaring a variable and doing months = age*m where m = 12.0 but is result is the same. By the way, the random value is about the same regardless of what variable age is. Why is this happening? Also, would this be a link-time error or run-time error?

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夜声 2025-01-09 17:59:35

您在初始化之前使用 age 进行乘法运算。您希望它能给您带来什么价值？

更改代码以首先获取年龄，然后进行乘法：

cout << "Enter your name and age: ";
cin >> name >> age;
months = age*12.0;

cout << "Hello " << name << " age " << age << " (" << months << " months)\n";

You're doing the multiplication using age before it's initialized. What value would you expect it to give you?

Change your code to first get the age, and then do the multiplication:

cout << "Enter your name and age: ";
cin >> name >> age;
months = age*12.0;

cout << "Hello " << name << " age " << age << " (" << months << " months)\n";

回复收藏 0 原文

牵你的手，一向走下去 2025-01-09 17:59:35

将月的计算移至输入点年龄之后（age在原始代码中未初始化）：

cout << "Enter your name and age: "; 
cin >> name >> age; 

months = age*12.0; 

cout << "Hello " << name << " age " << age << " (" << months << " months)\n";

Move the calculation of months to after the point age is entered (age was uninitialised in the original code):

cout << "Enter your name and age: "; 
cin >> name >> age; 

months = age*12.0; 

cout << "Hello " << name << " age " << age << " (" << months << " months)\n";

回复收藏 0 原文

~没有更多了~