Question

以下是我的代码。我的算法有问题。它显示输入文件中最大值和最小值的最后一个整数值。值。有人请看看，告诉我我做错了什么？

#include "cstdlib"
#include "iostream"
#include "fstream"

using namespace std;

int main()
{
    fstream instream;
    ofstream outstream;
    instream.open("num.txt");
    if(instream.fail())
    {
        cout<<"The input file failed to open\n";
        exit(1);
    }
    outstream.open("output.txt");
    if(outstream.fail())
    {
        cout<<"The output file failed to open";
        exit(1);
    }

    int next, largest, smallest;
    largest = 0;
    smallest = 0;

    while(instream>>next)
    {
        largest = next;
        smallest = next;
        if(largest<next)
        {
            largest = next;
        }
        if(smallest>next)
        {
            smallest = next;
        }
    }

    outstream<<"The largest number is: "<<largest<<endl;
    outstream<<"The smallest number is: "<<smallest<<endl;
    instream.close();
    outstream.close();
    return 0;
}

Answer 1

您无条件地在每次迭代中将next的值分配给largest和smallest：

while(instream>>next)
    {
        largest = next;    //  <--  Why are you surprised?
        smallest = next;   //  <--  :)
        if(largest<next)
        {
            largest = next;
        }
        if(smallest>next)
        {
            smallest = next;
        }
    }

Answer 2

程序倾向于做他们被告知的事情。这就是你要做的事情：

while(instream>>next) {
        largest = next;
        smallest = next;

这是您始终将它们设置为最新的地方。也许改变这三行：

largest = 0;
smallest = –0;
while(instream>>next) {

Answer 3

问题可能在这个循环中吗？

    while(instream>>next)

    {

    largest = next;

    smallest = next;

    if(largest<next)

    {

    largest = next;

    }

    if(smallest>next)

    {

      smallest = next;

    }

    }

2 if语句是不可以访问的，因为最大和最小都等于next？如果while中的2个if语句永远不会执行，则每次迭代时，最大值和最小值将始终设置为next。

Answer 4

#include<cstdlib>
#include<iostream>
#include<fstream>

using namespace std;

int main()
{
    fstream instream;
    ofstream outstream;
    instream.open("joy.txt");
    if(instream.fail())
    {
        cout<<"The input file failed to open\n";
        exit(1);
    }
    outstream.open("output.txt");
    if(outstream.fail())
    {
        cout<<"The output file failed to open";
        exit(1);
    }

    int next, largest, smallest;
    largest = 0;
    smallest = 0;


    while(instream>>next)
    {

        if(largest<next)
        {
            largest = next;
        }else{
                  smallest = next;
        }
    }

    outstream<<"The largest  number is: "<<largest<<endl;
    outstream<<"The smallest number is: "<<smallest<<endl;
    instream.close();
    outstream.close();

    system("pause");
    return 0;
}

如何显示从文件读取的整数的最小值和最大值？

4 个答案: