C语言实现字符串连接和字符串比较

c语言实现字符串连接和字符串比较

#include 
#include 
#include 
#include 
#include 
#include 

//字符串连接--将字符串src连接到目标字符串des的结尾 
char *mystrcat(char *des,const char *src)
{
    char *p=des;
    assert(des!=null && src!=null);
    while(*des!='\0')
    {
        des++;
    }

    while(*des++ = *src++);
    return p;
}

//字符串比较

int mystrcmp(char *str1,const char *str2)
{
    assert(str1!=null && str2!=null);
    int tmp;
    while((tmp = *str1 - *str2)==0 && *str1!='\0')
    {
        str1++;
        str2++;
    }
    return tmp;
}
int main()
{
    char str1[10]="ha";
    char str2[]="ppy";
    mystrcat(str1,str2);
    printf("%s\n",str1);

    printf("%d\n",mystrcmp("abc","abcd"));
    printf("%d\n",mystrcmp("abc","abc"));
    printf("%d\n",mystrcmp("abcd","abc"));

    return 0;
}

输出结果：