C + + do not use variables to find the method of strlen function of string length

This article illustrates the implementation method of C + + not using variables to find the strlen function of string length. Share to everyone for your reference. The implementation methods are as follows:

1, strlen source code to achieve:

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size_t strlen (const char *STR)//strlen does not make a memory illegal judgment, if it is null, will core. {const char *eos=str; while (*eos++); return (eos-str-1);}

2, common face questions will require not to use additional variables to achieve the Strlen function:

Achieve one:

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int strlen (const char *str) {if (' ==*str) return 0; else return strlen (str+1) +1;}

Realize two:

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int strlen (const char *str) {return *str? ( Strlen (str+1) +1): 0; }

I hope this article will help you with the C + + program design.