几个常考的关于字符串的函数实现

来源：互联网发布：做淘宝客怎么操作编辑：程序博客网时间：2024/04/30 13:31

一下实现包括strlen(), strcpy(), strncpy(), strcat(), strncat(), 等等

#include<iostream>using namespace std;int strlen1(const char *str){    int i = 0;    while (str[i] != '\0')    i++;    return i;}//赋值表达式返回左操作数 char *strcop1(char *des, const char *source){     if (des == source)     return des;     else     {         while (*des++ = *source++){};         return des;     } }char *strncop1(char *des, const char *source, int n){     if (des == source)     return des;     else     {         while ((n--) && (*source != '\0'))         {               *des++ = *source++;         }         *des = '\0';         return des;     }}int strcomp1(const char *des, const char *sou){    assert(des != NULL && sou != NULL);    while (*des == *sou && *des && *sou)    {          ++des;          ++sou;    }    return *des - *sou;}  char *strcat(char* &des, const char *source){     while (*des != '\0')     {           ++des;     }     while (*source != '\0')     *des++ = *source++;          *des = '\0';     return des;}int main(){    char *r= "HELLO world!";    int len = strlen1(r);    cout << "length:" << len << endl;        char *sour = "hello";    char arry[20];    //strcop1(arry, sour);    strncop1(arry, sour, 5);    puts(arry);        char *p = strcat(arry, r);    puts(p);        cout << strcomp1(r, arry) << endl;        system("pause");    return 0;}

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