C语言格式化输入输出函数使用

#include <stdio.h>

int main()
{
  int a[4];
  printf("please input:");
  //////////////////////////////////////////////////
  scanf("%d.%d.%d.%d",&a[0],&a[1],&a[2],&a[3]);
  int i = 0;
  for(;i < 4;i++)
   printf("a[%d] is %d\n",i,a[i]);
  //////////////////////////////////////////////////
  char b[64] = "192.168.1.1/255.255.255.0";
  int ip[4];
  int submask[4];
  sscanf(b,"%d.%d.%d.%d/%d.%d.%d.%d",&ip[0],&ip[1],&ip[2],&ip[3],&submask[0],&submask[1],&submask[2],&submask[3]);
  i = 0;
  for(;i < 4;i++)
   printf("ip[%d] is %d\n",i,ip[i]);
  i = 0;
  for(;i < 4;i++)
   printf("submask[%d] is %d\n",i,submask[i]);
  //////////////////////////////////////////////////
  char c[64];
  sprintf(c,"%d.%d.%d.%d/%d.%d.%d.%d",ip[0],ip[1],ip[2],ip[3],submask[0],submask[1],submask[2],submask[3]);
  printf("c is %s\n",c);
  return 0;
}

please input:10.120.136.85
a[0] is 10
a[1] is 120
a[2] is 136
a[3] is 85
ip[0] is 192
ip[1] is 168
ip[2] is 1
ip[3] is 1
submask[0] is 255
submask[1] is 255
submask[2] is 255
submask[3] is 0
c is 192.168.1.1/255.255.255.0