CODEWITHSUNDEEP
c++pointers
user3040961
user3040961

Reputation: 27

String Pointer in c++

I am trying to improve my programming skill and i've tried the exercise in my text book. I would like to ask a questions here:

char strng[] = " Hooray for All of Us ";
char *messPt;

messPt = &strng[0];
for(int i=0;i<20;i++)
    cout << *(messPt + i) << " ";
cout << endl;

messPt = strng;
while(*messPt++!= '\0')
    cout << *messPt ;
cout << endl;

and this is the output :

  H o o r a y   f o r   A l l   o f   U 
Hooray for All of Us

My questions are :

  1. actually at the end of the second output , there is a ? but it's in the reverse form. May anyone explain to me why this happen?

  2. if i declare the char like this : char strng[] = "Hooray for All of Us"; The second output become like this : ooray for All of Us

Thanks in advance :)

Upvotes: 1

Views: 93

Answers (1)

Mike Dinescu
Mike Dinescu

Reputation: 55720

That's because you are incrementing messPt when testing whether you've reached the end of the string in the while loop's condition:

 while(*messPt++ != '\0')    // tests *messPt = '\0' and also advances messPt by one
    cout << *messPt ;

You can refactor that to:

while(*messPt != '\0')
{
    cout << *messPt ;
    messPt++;
}

Or, if you are keen on being clever you can change it to this:

while(*messPt != 0)
    cout << *messPt++;

Sometimes the ++ operator can cause lots of hidden bugs. That's why some people argue it should be used sparingly.

Upvotes: 1

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