1000-2000以内润年
#include<stdio.h>
{
int i = 0;
for(i = 1000; i<=2000; i++)
{
if((i%400 == 0)||((i%4 == 0)&&(i%100 != 0)))
{
printf("%d ",i);
}
}
return 0;
}
打印乘法口诀表
#define ROW 9
#include<stdio.h>
int main()
{
int i = 0;
int j = 0;
for(i = 1; i<=ROW; i++)
{
for(j = 1; j<=i; j++)
{
printf("%d*%d=%2d ",i,j,i*j);
}
printf("\n");
}
return 0;
}
递归方法实现斐波那契
define _CRT_SECURE_NO_WARNINGS 1
#define M 10
#include<stdio.h>
int count = 0;
int fib(int n)
{
if(n == 3)
{
count ++;
}
if(n <= 2)
{
return 1;
}
else
{
return fib(n - 1) + fib(n - 2);
}
}
int main()
{
int n = M;
int z = 0;
fib(n);
printf("%d\n",fib(n));
printf("%d\n",count);
return 0;
}
递归实现n的阶乘
#include<stdio.h>
int Jc(int n)
{
if(n<=1)
{
return 1;
}
else
{
return n*Jc(n-1);
}
}
int main()
{
int n = 5;
Jc(n);
printf("%d\n",Jc(n));
return 0;
}
递归实现次方
#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int Cf(int n,int k)
{
if(k>0)
{
return n*Cf(n,k-1);
}
return 1;
}
int main()
{
int n = 2;
int k = 3;
Cf(n,k);
printf("%d\n",Cf(n,k));
return 0;
}
递归实现字符串逆置
#include<stdio.h>
#include<assert.h>
void strRev(char *str,int len)
{
assert(str);
if(*str == '\0')
return;
else
strRev(str+1,len-1);
printf("%c",*str);
}
int main()
{
char arr[] = {'1','2','3','4','5','\0'};
strRev(arr,5);
return 0;
}
二级指针传参
#include<stdio.h>
void test(int **ptr)
{
printf("num = %d\n",**ptr);
}
int main()
{
int n = 10;
int *p = &n;
int **pp = &p;
test(pp);
test(&p);
return 0;
}
非递归方法实现斐波那契
#define _CRT_SECURE_NO_WARNINGS 1
#define M 10
#include<stdio.h>
int fib(int n)
{
int result;
int pre_result;
int next_older_result;
result = pre_result = 1;
while(n > 2)
{
n -= 1;
next_older_result = pre_result;
pre_result = result;
result = pre_result + next_older_result;
}
return result;
}
int main()
{
int n = M;
fib(n);
printf("%d\n",fib(n));
return 0;
}
非递归实现n的阶乘
#include<stdio.h>
int Jc(int n)
{
int result = 1;
while(n>1)
{
result = result * n;
n = n - 1;
}
return result;
}
int main()
{
int n = 5;
Jc(n);
printf("%d\n",Jc(n));
return 0;
}
交换两个整数的内容
#include<stdio.h>
void change(int a, int b)
{
int tmp = a;
a = b;
b = tmp;
}
int main()
{
int a = 10;
int b = 20;
printf("%d %d\n",a,b);
change(a,b);
printf("%d %d\n",a,b);
return 0;
}
//
//
//
//
#include<stdio.h>
int main()
{
int a = 10;
int b = 20;
int tmp = 0;
printf("%d %d\n",a,b);
tmp = a;
a = b;
b = tmp;
printf("%d %d\n",a,b);
return 0;
}
//
//
//
//
#include<stdio.h>
void Swap(int *pa,int *pb)
{
int tmp = *pa;
*pa = *pb;
tmp = *pa;
}
int main()
{
int a = 10;
int b = 20;
printf("%d %d\n",a,b);
Swap(&a,&b);
printf("%d %d\n",a,b);
return 0;
}
冒泡实现字符串排序
#include <stdio.h>
#include <string.h>
void bubble_sort_str(char *str[],int sz)
{
int i = 0;
int j = 0;
for (i = 0; i < sz - 1; i++)
{
for (j = 0; j < sz - 1 - i; j++)
{
if (strcmp(*(str + j), *(str + j + 1))>0)
{
char *tmp = *(str+j);
*(str + j) = *(str + j + 1);
*(str + j + 1) = tmp;
}
}
}
}
int main()
{
int i = 0;
char *str[] = { "aacc", "bbbb", "dddd", "aaaa" };
bubble_sort_str(str,sizeof(str)/sizeof(*str));
for (i = 0; i < sizeof(str) / sizeof(str[1]); i++)
{
printf("%s ", *(str+i));
}
printf("\n");
return 0;
}
模拟实现strlen函数
#include<stdio.h>
#include<assert.h>
int my_strlen(char *str)
{
if(*str == '\0')
{
return 0;
}
else
{
return 1+ my_strlen(str+1);
}
}
int main()
{
char str[] = "abcdefg";
int len = my_strlen(str);
printf("%d\n",len);
return 0;
}
输出100-200内的素数
#include<stdio.h>
int main()
{
int i = 0;
int j = 0;
for(i = 100; i<=200; i++)
{
for(j = 2; j<=i-1; j++)
{
if(i%j == 0)
{
break;
}
if(i-1 == j)
{
printf("%d ",i);
}
}
}
printf("\n");
return 0;
}
字符串复制函数
#include<stdio.h>
char *my_strcpy(char *dest, const char *src)
{
char *tmp = dest;
while(*dest++ = *src++)
{
;
}
return tmp;
}
int main()
{
char arr1[] = "abcdefgh";
char arr2[20] = {0};
printf("%s\n",my_strcpy(arr2, arr1));
return 0;
}
字符串拼接函数
#include<stdio.h>
char *my_strcat(char *dest, char *src)
{char *temp = dest;
while(*dest)
{
dest++;
}
while(*dest++ = *src++)
{
;
}
return temp;
}
int main()
{
char arr1[20] = "abcde";
char arr2[20] = "12345";
printf("%s\n" ,my_strcat(arr1, arr2));
return 0;
}
内存拷贝
#include<stdio.h>
void *memcpy(void *dest, const void *src, int count)
{
void * ret = dest;
while(count--)
{
*(char *)dest = *(char *)src;
dest = (char *)dest + 1;
src = (char *)src+ 1;
}
return (ret);
}
int main()
{
char arr1[20] = {0};
//char arr1[20] = "abcdefg";
char arr2[20] = "1234";
int size = sizeof(arr2)/sizeof(arr2[0]);
printf("%s\n",memcpy(arr1, arr2, size));
return 0;
}