例题2.5—例题2.7

例题2.5原题

#include<iostream>
using namespace std;
int main()
{
	char ch;
	cout<<"please input a character:";
	cin>>ch;
	ch=ch>='a'&&ch<='z'?ch-'a'+'A':ch;
	//上述语句等价于ch=ch>='a'&&ch<='z'?ch-32:ch;
	cout<<"The result is:"<<ch<<endl;
	return 0;
}

例题2.5修改版

#include<iostream>
using namespace std;
int main()
{
	char ch;
	cout<<"please input a character:";
	cin>>ch;
	ch=ch>='A'&&ch<='Z'?ch-'A'+'a':ch;
	cout<<"The result is:"<<ch<<endl;
	return 0;
}

例题2.6原题

#include<iostream>
using namespace std;
int main()
{
	char ch='c';
	int a,b=13;
	float x,y;
	x=y=2.0;
	a=ch+5;
	x=b/2/x;
	y=b/y/2;
	cout<<"a="<<a<<endl;
	cout<<"x="<<x<<endl;
	cout<<"y="<<y<<endl;
	return 0;
}

例题2.6修改版

#include<iostream>
using namespace std;
int main()
{
	char ch='A';
	int a,b=13;
	float x,y;
	x=y=2.01;
	a=ch;//a赋值为65，ch先转化为int型（即字符A的ASCII值），再运算
	x=b/2*x;//x赋值为12.06，先做整除运算，再转换成double与x运算
	y=ch/2.0;//y赋值为32.5，ch先转化为int型，再转化为double型，在与2.0运算
	cout<<"a="<<a<<endl;
	cout<<"x="<<x<<endl;
	cout<<"y="<<y<<endl;
	return 0;
}

例题2.7原题

#include<iostream>
using namespace std;
int main()
{
	int ab,ac;
	double b=3.14;
	char c='A';
	ab=int(b);
	ac=int(c);
	cout<<"b="<<b<<endl;
	cout<<"ab="<<ab<<endl;
	cout<<"c="<<c<<endl;
	cout<<"ac="<<ac<<endl;
	return 0;
}