按值传递 和 按地址传递的例子

#include <stdio.h>void myswap(int, int);void ptr_myswap(int*, int*);int main(){    int a, b;    a = 3;    b = 5;    printf("in main, before call fun myswap(), a=%d; b=%d\n", a, b);    myswap(a, b);    printf("in main, after call fun myswap(), a=%d; b=%d\n\n", a, b);    ptr_myswap(&a, &b);    printf("in main, after call fun ptr_myswap(), a=%d; b=%d\n", a, b);    return 0;}void myswap(int x, int y){    int z;    printf("in fun myswap(), before swap x=%d; y=%d\n", x, y);    z = x;    x = y;    y = z;    printf("in fun myswap(), after swap x=%d; y=%d\n", x, y);}void ptr_myswap(int* xPtr, int *yPtr) {    int z;    printf("in fun ptr_myswap(), before swap x=%d; y=%d\n", *xPtr, *yPtr);    z = *xPtr;    *xPtr = *yPtr;    *yPtr = z;    printf("in fun ptr_myswap(),after swap x=%d; y=%d\n", *xPtr, *yPtr);}