Compare different length char arrays in c++ without string library

I have 2 char arrays, one with length 50, other whose length varies from 1...50. I need to compare these.

The problem is, that the array containing 50 chars, usually contains less chars, but when comparing, it also takes them into account. So if I have 2 array, whose value is U2, length开发者_StackOverflow社区 of first will be 50, the second - 2.

So, how do I check this, without using the standard string library? I must not use the string library, that is a prerequisite.

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If you aren’t allowed to use the standard library functionality then your first task is to re-program the required functionality. In your example, this would be strcmp.

Programming this function isn’t difficult – searching online should find you several possible implementations.

Roughly:

• Start walking through both strings in a loop until encountering a null char in either string.
• If both terminate in a null char at the same time, they are equal; otherwise the longer string is greater.
• Inside the loop, compare each individual character.
  • If the characters are equal, continue;
  • Otherwise, return.

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If the strings have different sizes, I think you are better with strncmp():

int strncmp(const char *s1, const char *s2, size_t n);

From the man pages:

It returns an integer less than, equal to, or greater than zero if s1 is found, respectively, to be less than, to match, or be greater than s2.

There's a custom implementation here to get you started.