#include <stdio.h>struct Biology
{bool living;
};struct Animal : Biology
{bool movable;void findFood() { }
};struct Plant : Biology
{bool growable;
};struct Beast : Animal
{void sleep(){ }
};struct Human : Animal
{void sleep() {printf("I'm sleeping...\n");}void work(){printf("I'm working...\n");}
};struct Girl : Human
{
private:int age;public:void play(){printf("I'm girl, I'm playing...\n");}void print(){age = 22;printf("Girl's age is %d\n", age);play();sleep();work();}
};struct Boy : Human
{
public:int age;void play(){printf("I'm boy, I'm playing...\n");}void print(){age = 23;printf("Boy's age is %d\n", age);play();sleep();work();}
};int main(int argc, char *argv[])
{Girl girl;girl.print();Boy boy;boy.print();printf("Press any key to continue...");getchar();return 0;
}

#include <stdio.h>int i = 1;struct Test
{
private:int i;public:int j;int getI(){i = 3;return i;}
};int main()
{int i = 2;Test test;test.j = 4;printf("i = %d\n", i);printf("::i = %d\n", ::i);//  printf("test.i = %d\n", test.i);printf("test.j = %d\n", test.j);printf("test.getI() = %d\n", test.getI());printf("Press any key to continue...");getchar();return 0;
}

#include"operate.h"bool Operator::setOperator(char op)
{bool ret = false;if( (op == '+')||(op == '-')||(op == '*')||(op == '/') ){ret = true;    mOp = op;}return ret;
}
void Operator::setParameter(double p1, double p2)
{mP1 = p1;mP2 = p2;
}
bool Operator::result(double& r)
{bool ret = true;switch(mOp){case '/':if((-0.000001 < mP2) && (mP2 <0.0000001)){ret = false;   }    else {r = mP1 / mP2; }break;case '+':r = mP1 + mP2; break;case '-':r = mP1 - mP2; break;case '*':r = mP1 * mP2; break;default:ret = false;break;        }  return ret;
}

#ifndef _OPERATE_H_
#define _OPERATE_H_class Operator
{public:bool setOperator(char op);void setParameter(double p1, double p2);bool result(double& r);private:  char mOp;double mP1;double mP2;};#endif 

#include <stdio.h>
#include"operate.h"int main(int argc, char *argv[])
{Operator op;double r = 0;op.setOperator('/');op.setParameter(6,0);if( op.result(r) ){printf("Result is %f\n",r);   }printf("Press any key to continue...");getchar();return 0;
}