[C++知识库]huyuhang-c++-复习01

编译型 C++

编译型: 先编译在执行,
解释语言 python 和 R 是逐行解释输出的
.cpp结尾的文件

#include <iostream>   // 头文件  相当于 python 的import
using namespace std;  // 命名空间  (标准)
// 主函数
int main(){
    cout<< "hello hu yu hang" <<endl;
}

c++ 声明变量

变量类型 变量名 =  变量值;
int a = b
float b = 99.9

/ 是整除

int main(){
    cout<< "hello hu yu hang" <<endl;
    int a = 10;
    int b = 4;
    float c = a/b;
    cout<< c << endl;
}

#include <iostream>
using namespace std;

int main (){
    // 前置++
    int a = 100;
    ++a;
    cout<< a <<endl;
    // 后置++
    int b = 100;
    b++;
    cout<< b <<endl;

    int c = ++a * 10 ;
//    int c = a++ * 10 ;
    cout<< "c = "<< c <<endl;
    cout<< "a = "<< a <<endl;

}

三目

#include <iostream>
using namespace std;
int main (){
    int a  = 100;
    int b  = 200;
    int c  = 300;
    int max ;
    if (a>b){
        max = a;
    } else{
        max = b;
    }

    int d = a > b ? a: b;
    cout<< d <<endl;
    cout<< max <<endl;

    cout <<"san  = "<<((a > b ? a : b) > c? (a > b ? a : b) :c)<<endl;

    return 0;
}

while和for循环

#include <iostream>
using namespace std;
int main (){
    // 1 ~ 100 奇数累加和
    int i = 1;
    int sum1 = 0;
    int sum2 = 0;
    while (i <= 100){
        if (i%2==1){
            sum1 += i;
        }
        i++;
    }
    cout<< "sum1 = "<< sum1 <<endl;

    // for
    for (int j = 1; j <= 100 ; j++) {
        if (j%2==0)
            sum2 += j;
    }
    cout<< "sum2 = "<< sum2 <<endl;

    return 0;
}