2.3 关系运算符和逻辑表达式

￡神魔★判官ぃ 2022-05-20 01:07 239阅读 0赞

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true等价于非0整型值，通常为1.

#include<iostream>
    #include<cstdio>
    using namespace std;
    int main()
    {
    	int n1 = 4, n2 = 5, n3;
    	n3 = ( n1 > n2);//(n1>n2)为false，n3=0
    	cout << n3 << "," ;//0,
    	n3 = (n1 < n2);//(n1<n2)为true，n3为非零值;
    	cout << n3 << ",";//1,
    	n3 = (n1 == 4);//n1==4为true，n3为非零值；
    	cout << n3 << ","; //1,
    	n3 = (n1 != 4);//n3=0;
    	cout << n3 << ",";
    	n3 = (n1==5);//n1==5为false ,n3=0;
    	cout << n3;
    	return 0; 
    	
    }

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第9页很重要

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#include<iostream>
    #include<cstdio>
    using namespace std;
    int main()
    {
    	int a = 0, b = 1;
    	bool n = (a ++) && (b ++);//(a ++)返回值为0，因此(b ++)不用再计算了,但a的值为1 
    	cout << a << "," << b << endl;//1,1
    	n = a ++ && b++ ;//a ++ 返回值为1，因此还要计算 b++，a=2，b=2 
    	cout << a << "," << b << endl;//2,2
    	n = a ++ || b++;//a ++返回值为2，为true，a变为3，因此b++不用再计算了 
    	cout << a << "," << b << endl;//3,2
    	return 0; 
    }

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