添加指针技巧

Author: yaouser

2指针开发技巧/10.c

@@ -0,0 +1,315 @@
+/****************************************
+技巧01：使用指针实现整数排序
+****************************************/
+/*
+#include <stdio.h>
+swap(int *p1,int *p2)
+{
+  int temp;
+  temp=*p1;
+  *p1=*p2;
+  *p2=temp;
+}
+exchange(int *pt1,int *pt2,int *pt3)
+{
+  if(*pt1<*pt2)
+    swap(pt1,pt2);
+  if(*pt1<*pt3)
+    swap(pt1,pt3);
+  if(*pt2<*pt3)
+    swap(pt2,pt3);
+}
+int main(int argc, char *argv[])
+{
+  int a,b,c,*q1,*q2,*q3;
+  puts("please input three key numbers you want to rank:");
+  scanf("%d%d%d",&a,&b,&c);
+  q1=&a;
+  q2=&b;
+  q3=&c;
+  exchange(q1,q2,q3);
+  printf ("%d,%d,%d\n",a,b,c);
+  puts("press any key to quit ...");
+  return 0;
+}
+*/
+/****************************************
+技巧02:使用指针实现数据交换
+****************************************/
+/*
+#include <stdio.h>
+swap(int *p1,int *p2)
+{
+  int temp;
+  temp=*p1;
+  *p1=*p2;
+  *p2=temp;
+}
+int main(int argc, char *argv[])
+{
+  int a,b;
+  int *pointer1,*pointer2;
+  printf ("please input two swap numbers:\n");
+  scanf("%d%d",&a,&b);
+  pointer1=&a;
+  pointer2=&b;
+  swap(pointer1,pointer2);
+  printf ("the result is :%d,%d\n",a,b);
+  return 0;
+}
+*/
+/****************************************
+技巧03：指向结构体变量的指针
+****************************************/
+/*
+#include <stdio.h>
+struct student   //自定义结构体
+{
+  int num;       //学生学号
+  char name[20]; //学生姓名,数组字符串
+  char sex;      //学生性别，字符
+  int age;       //学生年龄
+  float score;   //学生成绩
+};
+int main(int argc, char *argv[])
+{
+  //字符串用双引号，字符用单引号
+  struct student student1={1001,"liming",'M',20,92.5};//定义结构体变量
+  struct student *p;           //定义指针变量指向结构体类型
+  p=&student1;
+  printf ("number:%d\n",p->num);
+  printf ("name:%s\n",p->name);
+  printf ("sex:%c\n",p->sex);
+  printf ("age:%d\n",p->age);
+  printf ("score:%f\n",p->score);
+  return 0;
+}
+*/
+/****************************************
+技巧04:使用指针输出数组元素
+****************************************/
+/*
+#include <stdio.h>
+int main(int argc, char *argv[])
+{
+  int a[10];
+  int *p,i;
+  puts("please input ten integer:\n");
+  for(i=1;i<=10;i++)
+    scanf("%d",&a[i]);
+  printf ("\n");
+  for(p=&a;p<(a+10);p++)
+    printf ("%d ",*p);
+  return 0;
+}
+*/
+/****************************************
+技巧05：用指针实现逆序存放数组元素值
+****************************************/
+ /*
+#include <stdio.h>
+inverte(int *x,int n)
+{
+  int *p,temp,*i,*j,m=(n-1)/2;
+  i=x;
+  j=x+n-1;
+  p=x+m;
+  for (i=x;i<=p;i++,j--)
+    {
+      temp=*i;
+      *i=*j;
+      *j=temp;
+    }
+  return 0;
+}
+int main(int argc, char *argv[])
+{
+  int i,a[10]=
+    {1,2,3,4,5,6,7,8,9,0};
+  printf ("the elements of original array:\n");
+  for(i=0;i<10;i++)
+    printf ("%d ",a[i]);
+  printf ("\n");
+  inverte(a,10);
+  printf ("the elements has been inverted:\n");
+  for(i=0;i<10;i++)
+    printf ("%d ",a[i]);
+  printf ("\n");
+  return 0;
+}
+ */
+/****************************************
+技巧06：使用指针查找数列中最大值/最小值
+****************************************/
+/*
+#include <stdio.h>
+void max_min(int a[],int n,int *max,int *min)
+{
+  int *p;
+  *max=*min=*a;
+  for(p=a+1;p<a+n;p++)
+    {  
+      if(*p>*max)
+	*max=*p;
+      else if(*p<*min)
+	*min=*p;
+    }
+  return 0;
+}
+int main(int argc, char *argv[])
+{
+  int i,a[10];
+  int max,min;
+  printf ("input 10 integer numbers you want to operate:\n");
+  for(i=0;i<10;i++)
+    scanf("%d",&a[i]);
+  max_min(a,10,&max,&min);
+  printf ("the maximun number is:%d\n",max);
+  printf ("the maxinun number is:%d\n",min);
+  return 0;
+}
+*/
+/****************************************
+技巧07：使用指针实现字符串复制(复制函数没有写成功）
+****************************************/
+/*
+#include <stdio.h>
+copy(char *s,char *q)
+{
+  int i=0;
+  for (;*s!='\0';)
+    {
+      *q=*s;
+      s++;
+      q++;
+    }
+  *q='\0';
+}
+main()
+{
+  char *str,*p;
+  str="hello world!";
+  copy(str,p);
+  printf ("%s",p);
+  return 0;
+}
+*/
+/****************************************
+技巧08：使用指针实现字符串的连接(段错误，未成功）
+****************************************/
+/*
+#include <stdio.h>
+connect(char *s,char *t,char *q)
+{
+  int i=0;
+  for ( ; *s!='\0';  )
+    {
+      *q=*s;
+      s++;
+      q++;
+    }
+  for ( ; *t!='\0';  )
+    {
+      *q=*t;
+      t++;
+      q++;
+    }
+  *q='\0';
+}
+int main(int argc, char *argv[])
+{
+  char *str,*t,*p;
+  str="one world";
+  t="one dream";
+  printf ("the first string is:%s\n",str);
+  printf ("the second string is:%s\n",t);
+  connect(str,t,p);
+  printf ("the connected string is:\n");
+  printf ("%s",p);
+  return 0;
+}
+*/
+/****************************************
+技巧09：使用指针实现字符串插入(未成功）
+****************************************/
+/*
+#include <stdio.h>
+#include <string.h>
+insert(char *s,char *q,int n)
+{
+  int i=0;
+  char *str,strcp[50];
+  str=strcp;
+  for (i=0; *s!='\0'; i++)
+    {
+      if (i==n-1)
+	{
+	  for (; q!='\0'; )
+	    {
+	      str[1]=*q;
+	      q++;
+	      i++;
+	    }
+	}
+      str[i]=*s;
+      s++;
+    }
+  str[i+1]='\0';
+  return str;
+}
+int main(int argc, char *argv[])
+{
+  char *strin,*str;
+  int i;
+  str="hello world!";
+  strin ="big";
+  printf ("please input the position you want to insert:");
+  scanf("%d",&i);
+  str=insert(str,strin,i);
+  printf ("%s\n",str);
+  return 0;
+}
+*/
+/****************************************
+技巧10：使用指针实现字符串的匹配
+****************************************/
+/*
+#include <stdio.h>
+#include <string.h>
+int match(char *B,char *A)
+{
+  int i,j,start=0;
+  int lastB=strlen(B)-1;
+  int lastA=strlen(A)-1;
+  int endmatch =lastA;
+  for (j=0; endmatch<=lastB; endmatch++,start++)
+    {
+      if(B[endmatch]==A[lastA])
+	for(j=0,i=start;j<lastA&&B[i]==A[j];)
+	  i++,j++;
+      if (j==lastA)
+{
+  return (start+1);
+ }
+    }
+  if (endmatch>lastB)
+    {
+      printf ("the string is not matchable!\n");
+      return -1;
+    }
+}
+int main(int argc, char *argv[])
+{
+  char s[]="one world,one dream";
+  char t[]="world";
+  int p = match(s,t);
+  if (p!=-1)
+    {
+      printf ("Matchable!\n");
+      printf ("the start position is %d\n",p);
+    }
+  printf ("\n");
+  return 0;
+}
+*/
+