1. python是动态的，C++是静态的
   Python和C ++有着根本的区别。一个主要区别是C ++是静态类型的，而Python是动态类型的。

vehicle_doors = 4
vehicle_speed = 3.0
vehicle_acceleration = 1.5
vehicle_on = True
vehicle_gear = 'D'
vehicle_dors = vehicle_doors + 1

ython自动计算出vehicle_doors是一个整数，vehicle_speed是一个浮点数，vehicle_on是一个布尔变量。变量赋值是动态的。在Python中，不需要指定将进入变量的值的类型

在C ++中，上述代码都不起作用。在定义值之前，需要声明变量类型; 因此，C ++是一种静态类型语言。下面是代码的C ++版本：

int vehicle_doors;
float vehicle_speed;
float vehicle_acceleration;
char vehicle_gear;
bool vehicle_on;

vehicle_doors = 4;
vehicle_speed = 3.0;
vehicle_acceleration = 1.5;
vehicle_gear = 'D';
vehicle_on = True;

vehicle_doors = vehicle_doors + 1;

1. Python基于查看回车符和新换行符来检测代码行的结尾。C ++使用分号来实现相同的目的。
2. Python使用缩进将代码语句组合在一起，但C ++使用花括号。

3. Python是动态类型的，而C ++是静态类型的。就像你如何声明变量一样，你需要声明你的函数。

   
   
   

   因为C ++是静态类型的，所以需要指定函数输入变量的数据类型以及函数返回的数据类型。
   ···
   // Leave the main function as is

include<iostream>

float distance(float velocity, float acceleration, float time);
int main() {

// TODO: The following are examples you can use to test your code.
// You will need to uncomment them to get them working.

std::cout << distance(3, 4, 5) << std::endl;  
std::cout << distance(7.0, 2.1, 5.4) << std::endl;

return 0;   

}

//TODO: define your function
float distance(float velocity, float acceleration, float time){

float distance_;
distance_ = velocity * time + 0.5 * acceleration*time*time;
return distance_;

}
···

定义一个新的类型

typedef vector < vector <float> > t_grid; 

函数重载

bool close_enough(float v1, float v2) { 
    if (abs(v2-v1) > 0.0001 ) {
        return false;
    } 
    return true;
}

bool close_enough(vector < vector <float> > g1, vector < vector <float> > g2) {
    int i, j;
    float v1, v2;
    for (i=0; i<g1.size(); i++) {
        for (j=0; j<g1[0].size(); j++) {
            v1 = g1[i][j];
            v2 = g2[i][j];
            if (abs(v2-v1) > 0.0001 ) {
                return false;
            }
        }
    }
    return true;
}

bool test_normalize() {
    //declare several variables on one line
    vector < vector <float> > unnormalized, normalized, result; 

    unnormalized = zeros(2, 2);
    normalized = zeros(2,2);

    int i,j;

    for (i=0; i<2; i++) {
        for(j=0; j<2; j++) {
            unnormalized[i][j] = 1.0;
            normalized[i][j] = 0.25;
        }
    }

    result = normalize(unnormalized);

    bool correct;
    correct = close_enough(normalized, result);

    if (correct) {
        cout << "! - normalize function worked correctly!\n";
    }
    else {
        cout << "X - normalize function did not work correctly.\n";
        cout << "For the following input:\n\n";
        show_grid(unnormalized);
        cout << "\nYour code returned the following:\n\n";
        show_grid(result);
        cout << "\nWhen it should have returned the following:\n";
        show_grid(normalized);
    }
    return correct;
}

while

for loop

switch

#include <iostream>

int main() {

    char gear_status = 'N';

    switch(gear_status) {
        case 'D' :
            std::cout << "Driving Forward" << std::endl;
        case 'N' :
            std::cout << "Not Moving - Neutral" << std::endl;
        case 'P' :
            std::cout << "Not Moving - Parked" << std::endl;
        case 'R':
            std::cout << "Driving in Reverse" << std::endl;
    }

    std::cout << "Your car is currently in gear: " << gear_status << std::endl;

    return 0;
}