输入正整数或负整数列表，以使用开关函数 c++ 确定数字是偶数还是奇数

To input a list of positive or negative integers to find out if a number is even or odd using switch function c++

本文关键字：整数 c++ 数字 函数 开关 列表 输入      更新时间：2023-10-16
#include <iostream>
using namespace std;

限制是输入 10 个数字

const int LIMIT = 10;
int main ()
{

这只是声明变量

float counter ; 
int number ; 
int zeros;
int odds;
int evens;
cout << "Please enter " << LIMIT << "integers, "
<< "positive, negative, or zeros." << endl;
cout << "The numbers you entered are:" << endl;

从这里我尝试打印出用户输入的所有数字，并检查它是奇数还是偶数

for (counter = 1; counter <= LIMIT; counter++)
{
cin >> number;
switch(number % 2)
{
case 0:

所以在这里我试图将零算作偶数，所以如果列表为零，最后偶数的输出将包括零

if (number == 0 ){
zeros++;
evens++;
}
case 1:
case -1:
odds++;
}
}
cout << endl;
cout << "There are " << evens << " evens,"
<<"which includes " << zeros << " zeros."
<<endl;
cout << "The number of odd numbers is: " << odds
<< endl;
}

应初始化这些值：

int zeros = 0;
int odds = 0;
int evens = 0;

此外，对于偶数，evens的值必须递增。在您的代码中，它仅在number == 0的情况下递增。

switch(number % 2)
{
case 0:
if (number == 0 ) { zeros++; }
evens++; 
break;
case 1:
case -1:
odds++;
}

您还需要在case 0之后插入break。

我相信你的主要问题之一是你没有打破你的开关大小写标签。例如：

int a = 7;
switch(a)
{
case 7: cout << "case 7n";
case 1: // This will execute if case 7 doesn't have a break statement.
}

在您的情况下：

for (counter = 1; counter <= LIMIT; counter++)
{
cin >> number;
switch(number % 2)
{
case 0: if (number == 0 )
{
zeros++;
evens++;
} // Falls straight through to the next cases. Counting evens as odds
case 1:
case -1: odds++;
}
}

并且您仅在数字 == 0 时检测偶数，如果数模 2 等于 0，则不检测偶数。

这是一个重写的版本：

#include <iostream>
using namespace std;
const int LIMIT = 10;
int counter; // This is better as an int instead of a float
int number; // Also none of these variables need to be initialised
// As they are guaranteed to be zero-initialised as global static variables
int zeros;
int odds;
int evens;
int main ()
{
cout << "Please enter " << LIMIT << "integers, "
<< "positive, negative, or zeros." << endl;
for (counter = 1; counter <= LIMIT; counter++)
{
cout << "Enter number " << counter << " : ";
cin >> number;
switch (number % 2)
{
case 0:
if (number == 0) zeros++; // If input equals 0, increment zero counter
evens++; // Increment evens if in this case label
break; // Break, don't want to increment odds
default: odds++; // Default case, if not 0, must be odd.
}
}
cout << endl;
cout << "There are " << evens << " evens,"
<< "which includes " << zeros << " zeros." << endl;
cout << "The number of odd numbers is: " << odds << endl;
cin.ignore(); // This just discards the final 'n' newline character
cin.ignore(); // This blocks the program so the console doesn't close immediately
return 0;
}
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