C++-字符串(string) 布尔类型(bool)

字符串string 可以进行相加操作, s.size(), s.length(),s.c_str() 转换为c语言类型

/*
字符串演示
*/
#include <iostream>
#include <cstring>
using namespace std; 


int main(void) {
    string s = "hello"; 
    s += " world"; 
    cout << s << endl; 
    
    string s2; 
    s2 = s;
    cout << s << endl; 
    //进行比较 
    string s3 = "hello world"; 

    if (s == s3) {
        cout << "两个字符串内容相同" << endl; 
    }
    cout << s.size() << endl;
    cout << s.length() << endl; 
    cout << strlen(s.c_str()) << endl;  
}

 布尔类型 bool，真表示1，假表示0

/*
bool类型
*/
#include <iostream>

using namespace std; 


int main(void) {
    bool b = false; 
    cout << boolalpha << b << endl; //使得打印出来的数据是bool类型 boolalpha 
    cout << sizeof(b) << endl; 
    
    b = 3 + 5; 
    cout << "b=" << b << endl; 

    b = 1.2 * 3.4;
    cout << "b=" << b << endl; 
    
    char* p = NULL; 
    b = p; 
    cout << "b=" << b << endl;  //地址是空的话表示负数 
    return 0; 

}