C++柱形图反转

Question

我很困惑为什么我的列是颠倒的。实际的柱形图(仅星号)需要水平翻转。 (1900年人口为2000人，2040年人口为24000人。)

这是它目前的样子:

Population column chart

24000  **
23000  **
22000  **    **
21000  **    **
20000  **    **
19000  **    **
18000  **    **    **
17000  **    **    **
16000  **    **    **
15000  **    **    **
14000  **    **    **    **
13000  **    **    **    **
12000  **    **    **    **
11000  **    **    **    **
10000  **    **    **    **
 9000  **    **    **    **    **
 8000  **    **    **    **    **
 7000  **    **    **    **    **
 6000  **    **    **    **    **
 5000  **    **    **    **    **    **
 4000  **    **    **    **    **    **    **
 3000  **    **    **    **    **    **    **
 2000  **    **    **    **    **    **    **    **
 1000  **    **    **    **    **    **    **    **
      1900  1920  1940  1960  1980  2000  2020  2040

代码如下:

#include <fstream>
#include <iostream>
#include <iomanip>
using namespace std;

int main(){
    int population_size = 8; //Available for changes. 
    int year = 1900;
    int population[population_size];
    bool haveFile = true;

    const string inFileName = "people.txt";
    ifstream inFile("people.txt"); //Defines input file and opens

    cout << "Population column chart" << endl;
    cout << endl;


    if (inFile){
        // cout << "Open of " << inFileName << " was successful.\n";
        int count = 0;
        while (!inFile.eof()) {
            inFile >> population[count];
            count++;
        if (inFile.eof()) break;}

        int min = 1000; //Define minimum y-axis amount
        int max = 0; //Initialize max value to 0
        for (int i=0; i<count; i++){ //Find the maximum population 
            if(population[i]> max);
            max = population[i];
        }
         //This block creates the y-axis legend and rows of stars
        for (int num = max; num >= min; num = num - 1000){ 
            cout << setw(5) << num << " ";
            for (int year_counter = 0; year_counter <= count-1; year_counter++)
                if (num <= population[year_counter])
                    cout << setw(3) << "**" << "   ";
            cout << endl;
        }
        //This block creates the x-axis legend
        cout << "    "; 
        for (int k = 1; k <= count; k++){
            cout << setw(6) << year;
            year += 20;
        }
    }
}

问题出在这段代码中:

for (int year_counter = 0; year_counter <= count-1; year_counter++)
            if (num <= population[year_counter])
                cout << setw(3) << "**" << "   ";

population[0] 应该是 2000 的值，但它是 24000。我的数组以某种方式颠倒了吗？

提前致谢

Answer 1

 if(population[i]> max);
        max = population[i];

应该是

 if(population[i]> max)
        max = population[i];

试试看。

好的，我想我明白现在发生了什么。您正在尝试打印不同年份的人口。每列本质上是 6 个字符宽("\*\*" 在 setw(3) 中设置，加上 "")。问题是，如果要获取 "**"，您只打印该列；否则你什么都不打印。所以所有带有 "\*\*" 的列都挤在左边。

解决方案是始终为每一行打印该列，无论它是否获得 "**":

        for (int year_counter = 0; year_counter <= count - 1; year_counter++)
            if (num <= population[year_counter])
                cout << setw(3) << "**" << "   ";
            else                                    //NEW
                cout << setw(3) << "  " << "   ";   //NEW