C++ 串赋值时出现分段错误，怎么回事

Question

运行程序时，在串赋值时，老出现 Program received signal SIGSEGV, Segmentation fault怎么回事。
代码如下，定义了一个串，在一个串中查找另一个串，采用无回溯的匹配算法：

#include
#include
#define maxsize 50

using namespace std;

typedef struct
{
char ch[50];
int len;
} CHARS;

void getnext(CHARS *S,int next[])
{
int j,k;
j=1;
k=0;
next[1]=0;
while(jlen)
{
if((k==0)||(S->ch[j-1]==S->ch[k-1]))
{
k++;
j++;
next[j]=k;

    }
    else
    k=next[k];
}

}
int index(CHARS *S,CHARS *T,int next[])
{
int j,i;
j=1;
i=1;
while((i<=S->len)&&(j<=T->len))
{
if((j==0)||(S->ch[i-1]==T->ch[j-1]))
{
i++;
j++;
}
else j=next[j];
}
if(j>T->len)
return (i-T->len);
else
return 0;
}
int main()
{
CHARS *S,*T;
int ind;
void getnext(CHARS *S,int next[]);
int index(CHARS *S,CHARS *T,int next[]);
cout<<"please input a string :"< cin>>S->ch;
S->len=strlen(S->ch);
cout<<"the string is : "<ch;
cout<<"please input the string wanted equry: "< cin>>T->ch;
cout<<"the T -> ch is :"<ch< T->len=strlen(T->ch);

int next[T->len];
getnext(S, next);
ind=index(S,T,next);
return 0;

}

Answer 1

段错误？用什么未经初始化的指针了？