用指针实现 strncat（）

strncat（str1，str2,n）字符串有限追加

#include <stdio.h>#include <string.h>int main(){char str1[100];char str2[50];printf ("please input two strings:\n");gets(str1);gets(str2);int n;printf ("please input the number of additional:\n ");scanf ("%d",&n);char *p1;p1 = str1 + strlen(str1);char *p2 = str2;int i;for (i = 0;i < n; i++){*(p1++) = *(p2++);}*p1 = '\0';  printf ("the result is :\n");puts(str1);return 0;}