CODEWITHSUNDEEP
c++if-statementwhile-loop
Bartek Węgrzyn
Bartek Węgrzyn

Reputation: 57

While loop inside if-statement with the same condition inside?

One very experienced programmer wrote something like this:

#include <string>
using namespace std;

class Fraction
{
 float nominator;
 float denominator;

void load()
{
 cin>>nominator; cin>>denominator;
 if(denominator==0)
        {
          while(denominator==0)
          { 
            cout<<"denominator can not be equal 0!"<<endl;
            cin>>denominator;
          }
        }
}
};

I have no idea why there is an if statement. Is it really necessary?

Upvotes: 2

Views: 599

Answers (3)

Anselm_Peter
Anselm_Peter

Reputation: 11

From this code:

 if(denominator==0)
    {
      while(denominator==0)
      { 
        cout<<"denominator can not be equal 0!"<<endl;
        cin>>denominator;
      }
    }

I think if is only used for a teaching purpose to simply show that how flow will go to while after checking if condition. And how while loop will work further.

But if is not really required here. This code do the same: 

while(denominator==0)
{ 
  cout<<"denominator can not be equal 0!"<<endl;
  cin>>denominator;
}

Upvotes: 0

eerorika
eerorika

Reputation: 238461

Is it really necessary?

No, it is not necessary.

The shown snippet is equivalent to a program where the if statement is replaced with the contained loop statement.

Upvotes: 0

YSC
YSC

Reputation: 40150

In this particular example,

while(denominator==0)
{ 
  cout<<"denominator can not be equal 0!"<<endl;
  cin>>denominator;
}

would be exactly equivalent.

In the context you provided, nothing can tell us why someone would nest that loop in an useless if, but one could come up with explanations. In earlier version of that code, something could have been present inside the if block that changed the behavior of the program/function.

It also could be an innocent error.

Stroustrup's cat might have walked on their keyboard.

Upvotes: 4

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