interview test

base_8_16.c

#include<stdio.h>
int main(){
  int i = 0 ;
  printf("Plz enter a number:") ;
  scanf("%d",&i) ;
  printf("Base_10: %d\n",i) ;
  printf("Base_8: %o\n",i) ;
  printf("Base_16: %x\n",i) ;
	return 0;
}

compare_three.c

#include<stdio.h>
int main(){
	float x,y,z ;
  scanf("%f %f %f",&x,&y,&z) ;
  float tmp ;
  
  if(y>x) tmp=x,x=y,y=tmp;
  if(z>y) tmp=y,y=z,z=tmp;
  if(y>x) tmp=x,x=y,y=tmp;

  printf("%f > %f > %f\n",x,y,z) ;
	return 0;
}

fibonacci

#include<stdio.h>

int f(int n){
   if(n==1) return 0;
   if(n==2) return 1;
   return f(n-1) + f(n-2) ;
}


int main(int argc, char *argv[]){
   if(argc != 2){
      printf("Usage: ./fabonacci <Nth>\n") ;
      exit(0) ;
   }
   int n = atoi(argv[1]);   
   printf("%d\n", f(n)) ;
   return 0;
}

linked_list.cpp

#include<iostream>
#include<cstdio>
using namespace std;

typedef struct linked_list {
   int a ;
   struct linked_list *pnext ;
} list ;

int main(){
   list l1,l2,l3,l4 ;
   l1.a = 1, l1.pnext = &l2 ;
   l2.a = 2, l2.pnext = &l3 ;
   l3.a = 3, l3.pnext = &l4 ;
   l4.a = 4, l4.pnext = NULL ;
   
   list *ptr = &l1 ;
   while(ptr){
      printf("Value: %d\n", ptr->a) ;
      ptr = ptr->pnext ;
   }
   return 0;
}

oo.cpp

#include<iostream>
using namespace std;

class A {
public:
   A(){ cout << "A was borned." << endl ;}
   ~A(){ cout << "A was died." << endl ;}
   virtual void print(){ cout << "A's print()" << endl ;}
   void func(){ cout << "A's func" << endl ;}
};
class B : public A {
public:
   B(){ cout << "B was borned." << endl ;}
   ~B(){ cout << "B was died." << endl ;}
   virtual void print(){ cout << "B's print()" << endl ;}
   void func(){ cout << "B's func" << endl ;}
};
class C : public B {
public:
   C(){ cout << "C was borned." << endl ;}
   ~C(){ cout << "C was died." << endl ;}
   virtual void print(){ cout << "C's print()" << endl ;}
   void func(){ cout << "C's func" << endl ;}
};
int main(){
   C c ;
   B *b = (B*) &c ;
   A *a = (A*) &c ;

   b->print() ;
   b->func() ;
   
   a->print() ;
   a->func() ;
   return 0;
}

oo1.cpp

#include<iostream>
#include<cstdio>
using namespace std;

class Base {
   protected:
      int a,b,c ;
   public:
     Base(){
      a=1;b=2;c=3;
     } 
     int getA(){ return a; }
     virtual int getB(){ return b; }
     virtual int getC() = 0 ;
};

class Child : public Base {
   protected:
      int a,b,c ;
   public:
     Child(){
      a=4;b=5;c=6;
     } 
     int getA(){ return a; }
     int getB(){ return b; }
     int getC(){ return c; }

};

int main(){
   Child o ;
   Base *p = (Base*) &o ;
   int i1,i2,i3 ;
   i1 = p->getA() ;
   i2 = p->getB() ;
   i3 = p->getC() ;
   printf("%d %d %d\n",i1,i2,i3) ;
   return 0;
}

rand.c

#include<stdio.h>
#include<stdlib.h>
#include<time.h>

int main(){
	srand(time(NULL)) ;
  int i=0;
  int j=0;
  for(i=0;i!=6;++i){
    j = (rand()%100000)+1 ;
    printf("random number: %d\n",j) ;
  }
	return 0;
}

random.c

#include <algorithm>
#include <vector>
#include <iostream>
using namespace std ;

int main(){
   
   vector<int> v[10];

   random_shuffle(v.begin(),v.end());
   for(int i=0;i!=10;++i){
      cout << v[0] << endl ;
      rotate(v.begin(),v.begin()+1,v.end()) ;
   }
   return 0;
}

string.c

#include<stdio.h>
#include<string.h>
//how to reverse
void reverse(string &s){
   int len = s.length() ;
   string tmp(s) ;
   for(int i=0; i!=len; ++i){
      s[i] = tmp[ len-(i+1)] ;
   }
}

int main(){
  char result[100] ;
	char hello[] = "Hello" ;
  char world[] = " World" ;
  strcat(result,hello)  ;
  strcat(result,world)  ;
  puts(result) ;
  return 0;
}

swap.cpp

#include<iostream>
#include<cstdio>

using namespace std;
void swap(int &a, int &b){
   int tmp = a ; 
   a = b ;
   b = tmp ;
}
int main(){
   int x=1, y=2 ;
   printf("x=%d, y=%d\n",x,y) ;
   swap(x,y) ;
   printf("x=%d, y=%d\n",x,y) ;
   
   return 0;
}