prototype：extern int strlen(char *s);
usage：#include <>
Function: Calculate the length of the string s (unsigned int type)
illustrate: Returns the length of s, excluding the ending character NULL.
Give an example：
//
#include <>
#include <>
main()
{
char *s="Golden Global View";
clrscr();
printf("%s has %d chars",s,strlen(s));
getchar();
return 0;
}
Below are several source codes for implementing strlen function for your reference:
-------------------------------------------------1：start------------------------------------
#include <>
#include <>
typedef unsigned int u_int;
u_int Mystrlen(const char *str)
{
u_int i;
assert(str != NULL);
for (i = 0; str != '/0'; i++);
return i;
}
------------------------------------------------1：end--------------------------------------
-------------------------------------------------2:start--------------------------------------
int strlen(const char *str)
{
assert(str != NULL);
int len = 0;
while((*str++) != '/0')
len++;
return len;
}
------------------------------------------------2:end ------------------------------------------
------------------------------------------------3:start------------------------------------------
int strlen(const char *str)
{
assert(str);
const char *p = str;
while(*p++!=NULL);
return p - str - 1;
}
-------------------------------------------------4:end-----------------------------------------
-------------------------------------------------5:start----------------------------------------
int strlen(const char *str)
{
assert(str);
const char *p = str;
while(*p++);
return p - str - 1;
}
-----------------------------------------------6:end----------------------------------------
Let's briefly summarize:
The above implementation methods are similar, some use variables, and some use pointers.
Among them, the last one is recursive. In fact, when implementing library functions, it is not allowed.
For calling other library functions, here is just a method for you to implement strlen without variables.