#include"stdio.h"
int myf1(char s[]);
void myf2(char s2[],char s1[]);
int myf3(char s1[],char s2[]);
void main()
{
    char s1[20]={"i love beijing!"},s2[80]={"i love wuhan!"};
    printf("%d\n",myf1(s1));
    printf("%d\n",myf3(s1,s2));
    myf2(s2,s1);
    puts(s2);
}
int myf3(char s1[],char s2[])
{
    int i;
    for(i=0;s1[i]!='\0'||s2[i]!='\0';i++)
    {
        if(s1[i]<s2[i]) return -1;
        else if(s1[i]>2[i]) return 1;
    }
    return 0;
}
void myf2(char s2[],char s1[])
{
    int i;
    for(i=0;s1[i]!='0';i++)
        s2[i]=s1[i];
    s2[i]='\0';
}
int myf1(char s[])
{
    int i;
    for(i=0;;i++)
    {
        if(s[i]=='\0') break;
    }
    return i;
}

运行时这句有问题else if(s1[i]>2[i]) return 1;
显示
D:\c++程序 : error C2109: subscript requires array or pointer type

else if(s1[i]>2[i]) return 1;
s2[i]