1.函数

#include<stdio.h>

void Add(int *p)
{
  (*p)++;
}

int main()
{
  int time=0;
  Add(&time);
  printf("%d\n",time);
  return 0;
}

2.二分查找

#include<stdio.h>

void Add(int *p)
{
  (*p)++;
}

int main()
{
  int time=0;
  Add(&time);
  printf("%d\n",time);
  return 0;
}
[hym@VM-4-7-centos C_0610]$ cat binary_search.c
#include<stdio.h>

int binary_search(int arr[],int k,int sz)
{
  int left = 0;
  int right = sz-1;
  while(left<=right)
  {
    int mid = (left+right)/2;
    if(arr[mid]==k)
    return mid;
    else if(arr[mid]>k)
      right = mid-1;
    else
      left = mid+1;
  }  
   return -1;
}

int main()
{
  int arr [] = {1,2,3,4,5,6,7,8,9,10};
  int k = 7;
  int length = sizeof(arr)/sizeof(arr[0]);
  int ret = binary_search(arr,k,length);
  if(ret == -1)
  {
    printf("找不到\n");
  }
  else
  {
    printf("序号为%d\n",ret);
  }
  return 0;
}

3.函数调用

#include<stdio.h>

void fun(void)
{
  printf("hehe\n");
}

int main()
{
  fun();
  return 0;
}

4.  分文件编写

#include<stdio.h>
#include"test2.h"

int main()
{
  int ret = add(30,20);
  printf("%d\n",ret);
  return 0;
}
[hym@VM-4-7-centos C_0610]$ cat add.c
#include<stdio.h>

void Add(int *p)
{
  (*p)++;
}

#include"test2.h"
int add(int x,int y)
{
  return x+y;
}

5.函数

#include<stdio.h>

int get_max(int num1,int num2)
{
  return num1>num2?num1:num2;
}

int main()
{
  int a = 10;
  int b = 20;
  int max = get_max(a,b);
  printf("%d\n",max);
  return 0;
}

 

6.memset用法

#include<stdio.h>
#include<memory.h>

int main()
{
  char arr[] = "hello world"; 
  memset(arr,'x',5);
  printf("%s\n",arr);
  return 0;
}

 

 7.0到200的素数个数

#include<stdio.h>

int is_prime(int n)
{
  int i = 0;
  for(i=2;i<n;i++)
  {
    if(n%i==0)
      return 0;
  }
  return 1;
}

int main()
{
  int count=0;
  int i = 0;
  for(i = 100;i <= 200;i++)
  {
    if(is_prime(i)==1)
    {
      count++;
      printf("%d\n",i);
    }
  }
  printf("count = %d\n",count);
  return 0;
}

 8.strcpy用法

#include<stdio.h>
#include<string.h>

int main()
{
  char arr1[] = "abcdef";
  char arr2[] = {};
  strcpy(arr2,arr1);
  printf("%s\n",arr2);
  return 0;
}

9. 函数调用

#include<stdio.h>

void swap(int* x,int* y)
{
  int tmp = *x;
  *x = *y;
  *y = tmp;
}

int main()
{
  int a =10; 
  int  b = 20;
  printf("a=%d,b=%d",a,b);
  swap(&a,&b);
  printf("a=%d,b=%d",a,b);
  return 0;
}

 10.计算闰年

#include<stdio.h>

int is_leap_year(int y)
{
  if(y%4==0 && y%100!=0)
  return 1;
  else if(y%400 ==0)
    return 1;
  else
    return 0;
}

int main()
{
  int year = 0;
  for(year = 1000;year<=2000;year++)
  {
    if(is_leap_year(year)==1)
    {
      printf("%d ",year);
    }
  }
}