//实现两个串的连接
#include<stdio.h>
#include<stdlib.h>
typedef struct
{
    char *ch;
    int len;
}Hstring;
void concatstring(Hstring s,Hstring p,Hstring q)
{
    int i;
    s.ch=malloc((p.len+q.len)*sizeof(char));//根据所需容量申请空间
    for(i=0;i<p.len;i++)
        s.ch[i]=p.ch[i];
    for(i=0;i<q.len;i++)
        s.ch[i+p.len]=q.ch[i];
    s.len=p.len+q.len;
    puts(s.ch);
}
int main(void)
{
    int i;
    Hstring s,s1,s2;
    s1.len=0;
    s2.len=0;
    printf("请输入第一个字符串s1:\n");
        scanf("%s",s1.ch);
    printf("请输入第二个字符串s2:\n");
        scanf("%s",s2.ch);
    for(i=0;s1.ch[i]!='\0';i++)
        s1.len++;
    for(i=0;s2.ch[i]!='\0';i++)
        s2.len++;
    concatstring(s,s1,s2);
}
C:\Users\Administrator\Desktop\c21.c(27) : warning C4700: local variable 's1' used without having been initialized
C:\Users\Administrator\Desktop\c21.c(29) : warning C4700: local variable 's2' used without having been initialized
C:\Users\Administrator\Desktop\c21.c(34) : warning C4700: local variable 's' used without having been initialized

如何输入任意的字符串，而不是特定的呢

我编译了一下楼上的代码，但是还会出现这个警告c:\Users\Administrator\Desktop\c21.c(69) : warning C4700: local variable 's' used without having been initialized，不知道为什么？