program_6_4.cpp

c++程序设计讲义 cppprograming 含源码

// program 6.4: local scope
#include <iostream>
#include <stdlib.h>
#include <time.h>
using namespace std;
int main() {
   cout << "5 random numbers from 0 to 99:" << endl;
   srand( (unsigned int) time(0) );
   for ( int i=1; i<=5; ++i ) {
      cout << rand()%100 << endl;
   }
   // print i
   cout << "scope testing: i = " << i << endl;
   return 0;
}

// another example
#include <iostream>
using namespace std;
void Mystery(int a, int b); // prototype
int main() {
    int i = 10;
    int j = 20;
    Mystery(i, j);
    
    cout << a << endl;
    cout << b << endl;
    return 0;
}
void Mystery(int a, int b) {
    cout << a << endl;
    cout << b << endl;
    a = 1;
    b = 2;
    cout << a << endl;
    cout << b << endl;
    return;
}