c++爆红求高人帮助

ljx201129 @ 2024-07-22 21:20:27

#include <bits/stdc++.h>
using namespace std;
int main()
{
    int a, b;
    char c;
    cin >> a >> b >> c;
    if (c != '+' && c != '-' && c != '*' && c != '/' )
    {
        cout << "Invalid operator!";
        return 0;
    }
    if (c = '+')
    {
        cout << a+b;
        return 0;
    }
    if (c = '-')
    {
        cout << a-b;
        return 0;
    }
    if (c = '*')
    {
        cout << a*b;
        return 0;
    }
    if (c = '/')
    {
        if (b = 0)
        {
            cout << "Divided by zero!";
            return 0;
        }
        else
        {
            cout << a/b;
            return 0;
        }
    }
    return 0;
}

by are_you_sure @ 2024-07-22 21:24:46

@ljx201129 条件判断要用==，=是赋值

by are_you_sure @ 2024-07-22 21:25:27

把每个if里面的=改成==即可

by are_you_sure @ 2024-07-22 21:28:04

#include <iostream>
using namespace std;
int main()
{
    int a, b;
    char c;
    cin >> a >> b >> c;
    if (c != '+' && c != '-' && c != '*' && c != '/' )
    {
        cout << "Invalid operator!";
        return 0;
    }
    if (c == '+')
    {
        cout << a+b;
        return 0;
    }
    if (c == '-')
    {
        cout << a-b;
        return 0;
    }
    if (c == '*')
    {
        cout << a*b;
        return 0;
    }
    if (c == '/')
    {
        if (b == 0)
        {
            cout << "Divided by zero!";
            return 0;
        }
        else
        {
            cout << a/b;
            return 0;
        }
    }
    return 0;
}

其实你写的代码算很工整的了，我都写不出来这么工整的

by are_you_sure @ 2024-07-22 21:35:03

给你介绍一种很好用的算法：

switch(/*变量*/){
  case /*值*/:/*操作*/;break;
  default:/*操作*/;break;
}

```cpp
switch(c){
  case '+':cout<<a+b;break;
  case '-':cout<<a-b;break;
  default :cout<<"UNKNOW";break;
}

相当于

if(c=='+'){
  cout<<a+b;
}
if(c=='-'){
  cout<<a-b;
}
else{
  cout<<"UNKNOW";
}

by Obijeb @ 2024-07-22 21:36:22

@are_you_sure 然后就会一不小心忘写break导致死循环（）

by are_you_sure @ 2024-07-22 21:36:40

给你介绍一种很好用的算法：

switch(/*变量*/){
  case /*值*/:/*操作*/;break;
  default:/*操作*/;break;
}

下面

switch(c){
  case '+':cout<<a+b;break;
  case '-':cout<<a-b;break;
  default :cout<<"UNKNOW";break;
}

相当于

if(c=='+'){
  cout<<a+b;
}
if(c=='-'){
  cout<<a-b;
}
else{
  cout<<"UNKNOW";
}

by are_you_sure @ 2024-07-22 21:42:35

@Obijeb 额，不会死循环，只会挨个判断一遍，好像还会无脑全部执行一遍

by wisjsks @ 2024-07-24 12:37:46

if(xxxx=xxxx) {

    xxxxxxxxxx;

  xxxxxx;

} 里的“=”应换成“==”

if(xxxx==xxxx)

{

    xxxxxxxxxx;

   xxxxxx;

}

by Jason101 @ 2024-08-08 20:58:48

#include<bits/stdc++.h>
using namespace std;
int main()
{
    int a,b;    char c;
    cin >> a >> b >> c;
    if(c != '+'&&c != '-'&&c != '*'&&c != '/')
    {
        cout << "Invalid operator!";
    }
    else
    {
        int plus;
        if(c == '+')
        {
            plus = a + b;
            cout << plus;   
        }
        int m;
        if(c == '-')
        {
            m = a - b;
            cout << m; 
        }
        int mul;
        if(c == '*')
        {
            mul = a * b;
            cout << mul;
        }
        int ti;
        if(c == '/')
        {
            if(b == 0)
            {
                cout << "Divided by zero!";
            }
            else
            {
                ti = a / b;
                cout << ti;
            }
        }
    }
    return 0;
}

by zhangfengyao @ 2024-08-23 14:53:07

#include<iostream>
using namespace std;
int main()
{
    int a,b;
    char v;
    cin>>a>>b>>v;
    if(v=='+')
    {
        cout<<a+b<<endl;
    }
    else if(v=='-')
    {
        cout<<a-b<<endl;
    }
    else if(v=='*')
    {
        cout<<a*b<<endl;
    }
    else if(v=='/')
    {
        if(b==0)
        {
            cout<<"Divided by zero!"<<endl;
        }
        else
        {
            cout<<a/b<<endl;
        }
    }
    else
    {
        cout<<"Invalid operator!"<<endl;
    }
    return 0;
}