指针变量实现字符串的拼接，不用拼接函数。例如：s1:"apple" s2:"tree" 拼接后s1："appletree"

指针变量实现字符串的拼接，不用拼接函数。例如：s1:"apple" s2:"tree" 拼接后s1："appletree"

int main() {
 char s1[10]="apple";
 char s2[]="tree";
 char *p;
 int i;
 p=&s1[5];
 for (i=0;i<=4;i++) *p++=s2[i];
 return 0;
}