Char类型&Ascll码

#include<iostream>
using namespace std;
int main()
{
    char n;
	cin>>n;
	if((int)n>=90 && (int)n<=65)
	{
		cout<<"yes";
	}	
	else{
		cout<<"no";
	}
	return 0;
}

#include<iostream>
using namespace std;
int main()
{
    char n;
	cin>>n;
    n=n+32;
    cout<<n;
	return 0;
}

 
#include <iostream>
using namespace std;
int main() 
{
    char ch;
    cin >> ch;
    if (ch>='0' && ch<='9')
    {
        cout << "yes" << endl;
    } 
    else
    {
        cout << "no" << endl;
    }
    return 0;
}
 

#include <iostream>
using namespace std;

int main() 
{
    for(char c = 'a'; c <= 'z'; c++) 
    cout << c << " ";
}
return 0;
}

#include <iostream> 
using namespace std; 
int main() 
{
	char a,c,b,d; 
	cin >> a >> b >> c >> d;
	cout << a*c;
	return 0;
}

#include<iostream>
using namespace std;
int main()
{
	char ch;
	cin>>ch;
	if((int)ch>=65 && (int)ch<=90)
	{
	    ch=ch+32;
	}	
	else if((int)ch>=97 && (int)ch<=122)
	{
		ch=ch-32;
	}
	cout<<ch<<endl;
	return 0;
}