#include<assert.h>#include<stdio.h>int my_strlen(const char* strDest){    assert(NULL!=strDest);    if(‘\0‘==*strDest)        return 0;    else        return(1+my_strlen(++strDest));}int my_strlen1(const char* strDest){        assert(NULL!=strDest);        return (‘\0‘!=*strDest)?(1+my_strlen(strDest+1)):0;}int my_strlen2(const char* strDest){    if(strDest==NULL)        return 0;    int len=0;    //for(;*strDest++!=‘\0‘;)    while(*strDest++)    {        len++;    }    return len;}int my_strlen3(const char* strDest){    assert(strDest);    const char* p=strDest;    while(*p++);    return p-strDest-1;}int my_strlen4(const char* strDest){    assert(strDest);    const char *sc;    for(sc=strDest;*sc!=‘\0‘;++sc);    return sc-strDest;}int main(){    char* a="abcdefg";    char* b="";    char len,len1;    len  = my_strlen4(a);    len1 = my_strlen4(b);    printf("len=%d,len1=%d\n",len,len1);}