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#include <stdio.h>
#define SWAP(a,b) do ((&(a))!=(&(b)))?((a)^=(b)^=(a)^=(b)):((a)=(a)); while (0)
char *p1="1" ,*p2="2" ;
char c1=1 , c2=2 ;
short s1=1 , s2=2 ;
int i1=1 , i2=2 ;
__int64 I1=1i64, I2=2i64;
float f1=1.0f, f2=2.0f;
double d1=1.0 , d2=2.0 ;
void main() {
SWAP((int)p1,(int)p2); printf("char * %5s, %5s\n",p1,p2);
SWAP(c1,c2); printf("char %5d, %5d\n",c1,c2);
SWAP(s1,s2); printf("short %5d, %5d\n",s1,s2);
SWAP(i1,i2); printf("int %5d, %5d\n",i1,i2);
SWAP(I1,I2); printf("__int64 %5I64d,%5I64d\n",I1,I2);
SWAP(*(int *)&f1,*(int *)&f2);printf("float %5g, %5g\n",f1,f2);
SWAP(*(__int64 *)&d1,*(__int64 *)&d2);printf("double %5lg, %5lg\n",d1,d2);
SWAP(c1,c1);
printf("%d\n",c1);
}
//char * 2, 1
//char 2, 1
//short 2, 1
//int 2, 1
//__int64 2, 1
//float 2, 1
//double 2, 1
//2
void swap1(int *&p, int *&p1);
int main()
{
int a = 1, b = 2;
int *pa = &a, *pb = &b;
swap1(pa, pb);
cout << a << " " << b << endl;
}
void swap1(int *&p, int *&p1)
{
int *temp = p;
p = p1;
p1 = temp;
}
但是这只能是交换了pa和pb的值,与a和b是无关的
通过指针就可以交换a和b的值,如下:
void swap1(int *p, int *p1);
int main()
{
int a = 1, b = 2;
swap1(&a, &b);
cout << a << " " << b << endl;
}
void swap1(int *p, int *p1)
{
int temp = *p;
*p = *p1;
*p1 = temp;
}
通过引用也能达到目的:
void swap1(int &p, int &p1);
int main()
{
int a = 1, b = 2;
swap1(a, b);
cout << a << " " << b << endl;
}
void swap1(int &p, int &p1)
{
int temp = p;
p = p1;
p1 = temp;
}
#include <iostream>
using namespace std;
void swap1(int *&p, int *&p1);
int main()
{
int a = 1, b = 2;
swap(&a, &b);
cout << a << " " << b << endl;
}
void swap1(int *p, int *p1)
{
int *temp = *p;
*p = *p1;
*p1 = *temp;
}
这样就可以。加上&反而会让理解更复杂
void swap1(const int *&p, const int *&p1)
{
int temp = *p;
*p = *p1;
*p1 = temp;
}