C

#include <stdio.h>
int main( )
{
  int a = 80;
  printf("the input a is %d\n",a);
  printf("converse to 8 base is %#o\n", a);
  printf("converse to 16 base is %#X\n", a);
  printf("converse to char is %c\n", a);
  return 0;
}

#include<stdio.h> 
#include"math.h"
int main( )
{
  int i;
  int j;
  for (i = 2; i < 10; i++) {
    int temp = (int)sqrt(i);
    for (j = 1; j <= 1000; j++) {
      if (j != 1 && i%j == 0 ) {
        break;
      }else {
        if (j == temp) {
          printf("%d \n",i);
          break;
        }
      }
    }
  }
  return 0;
}

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

char* itoa(int val, int base){
  static char buf[32] = {0};
  int i = 30;
  for(; val && i ; --i, val /= base)
    buf[i] = "0123456789abcdef"[val % base];
  return &buf[i+1];
}

int main(int argc, char *argv[])
{
  int a = 100;
  char* str = itoa(a, 8);
  printf("%s \n",str);
  return 0;

}

#include <stdio.h>
#include <string.h>
int main(int argc, char *argv[])
{
  while(1){
    char a[3][10] = {"", "", ""};
    char b[100];
    scanf("%[^\n]", b);
    printf("b is %s\n", b);
    int j = 0;
    int i = 0;
    do{
      int k = 0;
      do{
        a[j][k] = b[i];
        i++;
        k++;
      }while(b[i] != ' ');
      printf("a[%d] iooooos %s\n", j, a[j]);
      j++;
      i++;
    }  while (j<3);
    scanf("%*[^\n]"); scanf("%*c");
  }
//  return 0;
  }

#include <sys/time.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

#define N 1000000

int current_timestamp() {
  struct timeval te; 
  gettimeofday(&te, NULL); // get current time
  int milliseconds = te.tv_sec*1000 + te.tv_usec/1000; // calculate milliseconds
  return milliseconds;
}

int main(int argc, char *argv[])
{
  float arr[N];
  float summation;
  int start, stop;
  for (int i = 0; i < N; ++i) {
    arr[i] = rand() % 100 / (float)100 ;
  }
  start = current_timestamp();
  for (int i = 0; i < N; ++i) {
    summation += arr[i];
  }
  stop = current_timestamp();
  printf("Summation is %f,  using time %d ", summation,  stop-start);
  return 0;
}

gcc task1_q1.c -o task1_q1
./task1_q1

#include <iostream>
int main(){
  int a[]={1,2,3,4,5};
  int *p = a;
  printf("Print this hallo!\n");
  printf("for value\n");
  printf("%d\n",*p);
  printf("%d\n",*a);
  printf("%d\n",a[0]);
  printf("%d\n",p[0]);
  printf("nihao :%d\n",*(p+1));
  printf("%d\n",*a+1);
  printf("%d\n",a[1]+1);
  printf("%d\n",p[1]+1);
  printf("for address:\n");
  printf("%d\n",p);
  printf("%d\n",a);
  printf("%d\n",&a[0]);
  printf("%d\n",p+2);
  printf("%d\n",&a[2]);
  printf("%c\n","0123456789abcdef"[3]);
  char *list = "0123456789abcdef";
  printf("%s\n",&list[10]);
  return 0;
}

#include <stdio.h>
void Point2order(int **a){
  printf("**a : %d\n",**a );
  printf("*a  : %d\n",*a );  
  printf(" a  : %d\n", a );
  printf("&a  : %d\n",&a );
  printf("\n");
  int *z = *a;
  printf("  int *z = *a : if z = *a\n");
  printf("z  : %d\n", z );
  printf("*a : %d\n", *a );
  printf("if *z = **a\n");
  printf("*z :%d\n", *z );
  printf("**a:%d\n",  **a );
  printf("\n");
  int *y = a;
  printf("  int *y = a : if y = a\n");
  printf("y  : %d\n", y );
  printf("a  : %d\n", a );
  printf("if *y = *a\n");
  printf("*y : %d\n", *y );
  printf("*a : %d\n",  *a );
  printf("\n");
  int *x = &a;
  printf("  int *x = &a : if x = &a\n");
  printf("x  : %d\n", x );
  printf("&a : %d\n", &a );
  printf("if *x = *(&a)\n");
  printf("*x : %d\n", *x );
  printf("*&a: %d\n",  *(&a) );
}
int main(int argc, char *argv[])
{

  int aa[] = {10,20,30};
  int *a = aa;
  Point2order(&a);
  return 0;
}

#include <stdio.h>
int main(){
  int a[3][4]={0,1,2,3,4,5,6,7,8,9,10,11};
  int(*p)[4];
  int i,j;
  p=a;
  for(i=0; i<3; i++){
    for(j=0; j<4; j++) printf("%2d  ",*(*(p+i)+j));
    printf("\n");
  }
  printf("\n");

  int *m[4] = {a[0],a[1],a[2],a[3]};
  for(i=0; i<3; i++){
    for(j=0; j<4; j++) printf("%2d  ",*(*(m+i)+j));
    printf("\n");
  }

  return 0;
}

#include <stdio.h>
void funaa(char **p){
  printf("address mani after 2\n");
  printf("funaa : %c\n", *p[0] );
}
void funbb(int **p){
  printf("address mani after 2\n");
  printf("funbb : %d\n", *p[0] );
}
void funa(char **p){
  printf("value mani: \n");
  printf("funa: the first %c\n", **p );
  printf("funa: the third %c\n", *(   (*p+1)    +1)      );
  char *pa = *p+2;
  funaa(&pa);
  }
void funb(int **p){
  printf("\n");
  printf("value mani: \n");
  printf("funb: the first %d\n", **p );
  printf("funa: the third %d\n", *(   (*p+1)    +1)       );
  int *pa = *p +2;
  funbb(&pa);
}

void funChar2OrderPoint(char ** p){
  printf("\n");
  printf("point arrar[0][0]:%c\n", *( *(p+0) +0)           );
  printf("point arrar[0][1]:%c\n", p[0][1]                 );
  printf("point arrar[0][2]:%c\n", *( *(p+0) +2)           );
  printf("point arrar[1][0]:%c\n", *( *(p+1) +0)           );
  printf("point arrar[1][1]:%c\n", *( *(p+1) +1)           );
  printf("point arrar[1][2]:%c\n", *( *(p+1) +2)           );
  printf("point arrar[2][0]:%c\n", *( *(p+2) +0)           );
  printf("point arrar[2][1]:%c\n", *( *(p+2) +1)           );
  printf("point arrar[2][2]:%c\n", *( *(p+2) +2)           );
}
void funInt2OrderPoint(int ** p){
  printf("\n");
  printf("point arrar[0][0]:%d\n", *( *(p+0) +0)           );
  printf("point arrar[0][1]:%d\n", *( *(p+0) +1)           );
  printf("point arrar[0][2]:%d\n", p[0][2]                 );
  printf("point arrar[1][0]:%d\n", *( *(p+1) +0)           );
  printf("point arrar[1][1]:%d\n", *( *(p+1) +1)           );
  printf("point arrar[1][2]:%d\n", *( *(p+1) +2)           );
  printf("point arrar[2][0]:%d\n", *( *(p+2) +0)           );
  printf("point arrar[2][1]:%d\n", *( *(p+2) +1)           );
  printf("point arrar[2][2]:%d\n", *( *(p+2) +2)           );
}
int main(int argc, char *argv[])
{
  /* char 一维数组转二级指针 */
  char a[] ="1234567";
  char *pa = a;
  funa(&pa);
  /* int 一维数组转二级指针 */
  int b[] = {1,2,3,4,5,6,7};
  int *pb = b;
  funb(&pb);
  /* char 指针数组转二级指针 */
  char a1[] ="123";
  char a2[] = "456";
  char a3[] = "789";
  char *chara [] = {"123", "456", "789"};
  char **poa = chara;
  funChar2OrderPoint(poa);
  printf("\n");
  printf("%s\n", *chara+2 );
  printf("%s\n", *chara+1 );
  printf("%s\n", *chara   );
  printf("\n");
  printf("%s\n", chara[0] );
  printf("%s\n", chara[1] );
  printf("%s\n", chara[2] );
  printf("\n");
  printf("%c\n",      chara[1][2]         );
  printf("%c\n",*(    chara[1]      +2)   );
  printf("%c\n",*(   *(chara+1)     +2)   );

  /* int 指针数组转二级指针 */
  int b1[] = {1,2,3};
  int b2[] = {4,5,6};
  int b3[] = {7,8,9};
  int *intb [3] = {b1, b2, b3};
  int **pob = intb;
  funInt2OrderPoint(pob);
  printf("\n");
  printf("如果打开评论，可以执行，但是会报警告，结果是对应元素的地址\n");
  // printf("%d\n", *intb+2 ); //&3
  // printf("%d\n", *intb+1 ); //&2
  // printf("%d\n", *intb   ); //&1
  // printf("\n");
  // printf("%d\n", intb[0] );  //&123
  // printf("%d\n", intb[1] );  //&456
  // printf("%d\n", intb[2] );  //&789
  printf("\n");
  printf("%d\n",      intb[1][2]         );
  printf("%d\n",*(    intb[1]      +2)   );
  printf("%d\n",*(   *(intb+1)     +2)   );

  return 0;
}

#include <stdio.h>

int main(int argc, char *argv[])

{ 
  char **p1 = argv;
  printf("%c \n", argv[1][2]   );
  printf("%c \n", p1[1][2]     );
  printf("%c \n", *(*(p1+1)+2) );


  int b2[] = {1, 2, 3, 4, 5};
  int *a2 = b2;
  int **p2 = &a2;
  printf("%d \n", a2[1]         );
  printf("%d \n", *(a2+1)       );
  printf("%d \n", p2[0][1]      );
  printf("%d \n", *(*(p2+0)+1)  );

  int m[] = {1,2};
  int n[] = {3,4};
  int *a3[] = {m, n};
  int **p3 = a3;
  printf("%d \n", a3[0][1]      );
  printf("%d \n", p3[0][1]      );
  printf("%d \n", *(*(p3+0)+1)  );

  return 0;

  int a4[][2]  ={{1,2},{3,4}};
  int (*p4)[2] = a4;
  printf("%d \n", a4[1][0]      );
  printf("%d \n", p4[1][0]      );
  printf("%d \n", *(*(p4+1)+0)  );

}

#include <iostream>
using namespace std;

class Animal
{
public:
  Animal();
  virtual run();
};
Animal::Animal(){};
void Animal::run(){cout <<"Animal is running"<<endl;}

class Dog : public Animal
{
public:
  Dog();
  virtual run();
};
Dog::Dog(){};
void Dog::run(){cout <<"Dog is running"<<endl;}

Animal *p = new Animal;
p->run();
p = new Dog;
p->run();
//此时的p就是多态变量，但是只有这个变量先由基类生成，再指向子类
//反之时不能的

class Animal(object):
    def __init__(self):
        self.name ='Animal name'
    def run(self):
        print('Animal is running')

class Dog(Animal):
    def __init__(self):
        self.name ='Dog name'
    def run(self):
        print('Dog is running')

# Polymorphism, all Class or instance will be checked the best passing
# mothode or character
def run_twice(a):
    a.run()
def name(b):
    print(b.name)

ani = Animal()
ani.name
ani.run()

ani = Dog()
ani.name
ani.run()

class Figure {
    double dim1;
    double dim2;
    Figure(double d1, double d2) {
        // 有参的构造方法
        this.dim1 = d1;
        this.dim2 = d2;
    }
    double area() {
        // 用于计算对象的面积
        System.out.println("父类中计算对象面积的方法，没有实际意义，需要在子类中重写。");
        return 0;
    }
}

class Rectangle extends Figure {
    Rectangle(double d1, double d2) {
        super(d1, d2);
    }
    double area() {
        System.out.println("长方形的面积：");
        return super.dim1 * super.dim2;
    }
}

class Triangle extends Figure {
    Triangle(double d1, double d2) {
        super(d1, d2);
    }
    double area() {
        System.out.println("三角形的面积：");
        return super.dim1 * super.dim2 / 2;
    }
}

public class Test {
    public static void main(String[] args) {

        Figure figure = new Rectangle(9, 9);
        System.out.println(figure.area());
        System.out.println("===============================");
        figure = new Triangle(6, 8);
        System.out.println(figure.area());
        System.out.println("===============================");
        figure = new Figure(10, 10);
        System.out.println(figure.area());

    }
}

int b[] = {b1, b2, b3};
  printf("niiiiilhakkko\n");
  printf("%d\n", input);
  printf("%d\n", b2);
  for(int i = 0; i<3;i++){
    printf("%d", b[i]);
   }