静态变量（多个源文件）

可以和全局变量（多个源文件）做个对比

//sortnum.h

#ifndef _SORTNUM_H_ #define _SORTNUM_H_#include <iostream>using namespace std;int sortnum(double *p1, double *p2);#endif

//sortnum.cpp

#include "sortnum.h"int sortnum(double *p1, double *p2){ static int ncount = 0; //静态局部变量，ncount的作用域只用于该函数，所以要有一个返回值供main.cpp调用 double temp; temp = *p1; *p1 = *p2; *p2 = temp; return ++ncount; }

 //main.cpp

#include <cstdlib>#include <iostream>#include "sortnum.h"int main(double argc, char *argv[]){ double a[10]; int i, j, ncount = 0; cout << "Please input ten numbers:"; for(i = 0; i < 10; i++) cin >> a[i]; for(i = 0; i < 10; i++) for(j = i + 1; j < 10; j++) if(a[i] > a[j]) ncount = sortnum(&a[i], &a[j]); cout << "The new order is:" << " "; for(i = 0; i < 10; i++) cout << a[i] << " "; cout << '/n'; cout << "共进行" << ncount << "次交换" << '/n'; system("PAUSE"); return EXIT_SUCCESS;}