(3)连接运算 strconcat(S1S seqstring strconcat(seqstring sl, seqstring $2) int i; segstril Ing sk if(sIlength+S2,length>MAXSIZE i printf("cannot concat); return NULL) else &r(seqstring* )malloc(sizeof(seqstring); for(i=0; K<S1. length; i++)r->str= SIstri for (i=0; i<S2, length; i++) r->strI s1length+i]= S2 stril: r->length= SI length+ S2. length; r->strIr->length =10; return (r:（3）连接运算strconcat(S1 ,S2 ) seqstring * strconcat(seqstring S1,seqstring S2) { int i; seqstring *r; if (S1.length+S2.length>MAXSIZE) { printf("cannot concate"); return(NULL);} else { r=(seqstring*)malloc (sizeof(seqstring)); for (i=0; i<S1.length;i++) r->str[i]= S1.str[i]; for (i=0; i<S2.length;i++) r->str[ S1.length+i]= S2.str[i]; r->length= S1.length+ S2.length; r->str[r->length]='\0'; } return (r); }