CODEWITHSUNDEEP
c++arrayschar
Daniel Del Core
Daniel Del Core

Reputation: 3221

Remove First two Characters from a Char array

I'm having trouble removing the first two characters from my char array.

 input[MAXSIZE] = "./hello";

 for(int i = 2; i < MAXSIZE; i+=2)
 {
    strcpy(input[i-2],input[i]);
 }

and I'm getting the following errors:

 invalid conversion from ‘char’ to ‘char*’
 initializing argument 1 of ‘char* strcpy(char*, const char*)’
 invalid conversion from ‘char’ to ‘const char*’
 initializing argument 2 of ‘char* strcpy(char*, const char*)’

I know that this is a very basic problem but im fairly new to this. Also if there is an easier way to get around this problem feel free to educate me.

Upvotes: 0

Views: 14049

Answers (4)

Dennis
Dennis

Reputation: 3731

As an alternative solution you can simply use a pointer to char to "skip" the first two characters in the array:

char input[MAXSIZE] = {0};
snprintf_s<MAXSIZE>(input, _TRUNCATE, "./hello" ); //MSVC only
char* noDotSlash = input + 2;
cout << noDotSlash << endl; //should print just hello.

Upvotes: 1

Rohit Vipin Mathews
Rohit Vipin Mathews

Reputation: 11787

strcpy has to be used on char array not characters!!

Also look into this Que c remove the first character of an array

Upvotes: 0

Jon
Jon

Reputation: 437336

As others have said, strcpy is not meant to be used like that and you can achieve the desired effect with

// loop step changed to 1; i += 2 is a mistake
for(int i = 2; i < MAXSIZE; ++i)
{
    input[i-2] = input[i];
}

However, you can also simply use memmove:

memmove(input, input + 2, (MAXSIZE - 2) / sizeof(input[0]));

If input is guaranteed to be an array of char you can also remove the / sizeof(input[0]) part.

And of course even better would be to do it the standard library way, using std::copy_backward (necessary because the source and destination ranges overlap):

#include <algorithm>
std::copy_backward(input + 2, input + MAXSIZE, input + MAXSIZE - 2);

Upvotes: 2

Luchian Grigore
Luchian Grigore

Reputation: 258568

strcpy copies null terminated char arrays, not characters.

What you want is:

input[i-2] = input[i];

Also, why don't you increment i with 1 but with 2?

Upvotes: 3

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