Day 1: Data Types

布满荆棘的人生 2022-03-27 08:58 128阅读 0赞

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3podWlxaXV6aHVveXVlNTgz_size_16_color_FFFFFF_t_70][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3podWlxaXV6aHVveXVlNTgz_size_16_color_FFFFFF_t_70 1][]

Python3代码：

i = 4
    d = 4.0
    s = 'HackerRank '
    # Declare second integer, double, and String variables.
    
    # Read and save an integer, double, and String to your variables.
    i2= int(input())
    d2=float(input())   //这里保留小数点后一位，使用float类型
    s2=input()
    # Print the sum of both integer variables on a new line.
    print(i+i2)
    # Print the sum of the double variables on a new line.
    print(d+d2)
    # Concatenate and print the String variables on a new line
    # The 's' variable above should be printed first.
    print(s+s2)

C++代码：

#include <iostream>
    #include <iomanip>  // 操作符，用于保留小数点位数
    #include <limits>
    
    using namespace std;
    
    int main() {
        int i = 4;
        double d = 4.0;
        string s = "HackerRank ";
    
        
        // Declare second integer, double, and String variables.
        int i2;  
        double d2;
        string s2;
        // Read and save an integer, double, and String to your variables.
        cin>> i2; 
        cin>>d2; 
        cin.ignore();//also use getchar()  这里忽略输入字符串中的空格
        getline( cin, s2 );
        // Note: If you have trouble reading the entire string, please go back and review the Tutorial closely.
        
        // Print the sum of both integer variables on a new line.
        cout<<(i+i2)<<endl;
        // Print the sum of the double variables on a new line.
        cout<<fixed<<setprecision(1)<<(d+d2)<<endl;  //保留小数点后一位
        // Concatenate and print the String variables on a new line
        // The 's' variable above should be printed first.
        cout<<s+s2<<endl;
        return 0;
    }

总结：

1.python中，保留小数点后一位，使用float类型

d2=float(input())   //这里保留小数点后一位，使用float类型

2. 使用 cin.ignore()，忽略输入字符串中的空格

string s2; 
    cin.ignore();  //also use getchar()   忽略输入字符串中的空格
    getline( cin, s2 );

3.C++中，保留小数点后一位，使用  <iomanip> 中的 fixed 和 setprecision(1)

#include <iomanip>
     
    cout<<fixed<<setprecision(1)<<(d+d2)<<endl;

4.C++保留有效数字的位数，只许使用  setprecision(n)，n 指 有效数字位数。

#include <iomanip>
    
    float a = 123.666;
    cout<<setprecision(5)<<a; //保留5位有效数字
    
    输出 123.67（注意四舍五入）

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3podWlxaXV6aHVveXVlNTgz_size_16_color_FFFFFF_t_70]: /images/20220327/d42c3f84590242f6a870918c38ee5b62.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3podWlxaXV6aHVveXVlNTgz_size_16_color_FFFFFF_t_70 1]: /images/20220327/6040b905c058486cbdd1a5c6aa34432e.png