Question

C语言 用指针调换两个数的位置！

例如输入12 输出21

Answer 1

#include <stdio.h>
inverse(int *p)
{int m,n,num,num1;
num=*p;//输入数字
num1=0;
m=num;
while(m)
{n=m%10;//求个位
num1=num1*10+n;//反序
m=m/10;
}
*p=num1;
}

main()
{int in_data,out_data;
int *p=&in_data;
printf("Please input the number:");
scanf("%d",&in_data);
inverse(p);
out_data=*p;
printf("The inverse number is:");
printf("%d\n",out_data);
}
程序结果：
Please input the number:123
The inverse number is:321

Answer 2

#include<iostream.h>
int main()
{
char a[2];
cout<<"请输入一个数"<<endl;
cin>>a;
//cout<<a[1];
char *p=a;
char *q=p+1;
//cout<<*p<<endl;
for(int i=1;i<3;i++)
cout<<*q--;
cout<<endl;

}

Answer 3

#include "stdio.h"
#include "math.h"
void main()
{
int a,b;
void swap(int *apoint,int *bpoint);

scanf("%d%d",&a,&b);
swap(&a,&b);
printf("%d%d",a,b);
}
void swap(int *apoint,int *bpoint)
{
int t;
t=*apoint;
*apoint=*bpoint;
*bpoint=t;
}