CODEWITHSUNDEEP
c++validationcharacter-arrays
Josip Dorvak
Josip Dorvak

Reputation: 131

c++ char array size validation

I have a character array that can hold 1000 elements (+1 for the '\0'). The array will be filled by user input. I was wondering if there is any way of checking if the input is more than what the array can hold. If I do try to add it, the program will crash before I can compare its size. I was thinking expand the array and see if the input is less than 1000 characters, but that idea doesn't seem like a really good one too me.

EDIT:

im using std::cin.getline() to get input from the user and can't use the Sting class

Upvotes: 0

Views: 891

Answers (2)

Zac Howland
Zac Howland

Reputation: 15872

Short answer: yes.

Use std::string:

std::string line
while (std::getline(std::cin, line))
{
    // do something with line
}

If you are not allowed to use std::string, then you can either role your own string class, or look at common implementations of std::getline and mimic them (just without storing it in a std::string).

Upvotes: 1

CS Pei
CS Pei

Reputation: 11047

I think one way to check it is to find the index of \0 in your array. If the position is equal or greater than 1000, then you should not add more chars to it.

If you are using cin.getline() you can use a variable n to specify the maximum of chars you want 

istream& getline (char* s, streamsize n );
istream& getline (char* s, streamsize n, char delim );

Here you can set n=1001 (it also counts the termination char \0).

Upvotes: 1

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