第七天日志"/>
第七天日志
请编写一个C函数,该函数将一个字符串逆序
#include <stdio.h>
#include <string.h>
char *reserve(char *s)
{
int i; //定义循环变量
int n = strlen(s)/2; //循环次数只能到字符串长度的一半,否则待会交换又会换回来
char tmp;
for(i = 0; i <= n; i++) //这里用的是字符数组处理字符串,将字符串的首字符和最后一个字符交换,注意交换的次数
{
tmp = s[i];
s[i] = s[strlen(s)-i-1];
s[strlen(s)-i-1] = tmp;
}
return s; //结果返回交换后的字符串
}
int main()
{
char str[20];
printf("Please input a string:\n");
scanf("%s", str);
printf("\nThe reserved string is:\n%s\n", reserve(str));
return 0;
}
请编写一个C函数,该函数可以实现将一个整数转为任意进制的字符串输出
坐忘含光 2018/7/15 10:36:56
int main()
{
int num,n;
printf("Please enter a number to change:");
scanf("%d",&num);
printf("请输入要转换的进制(如2或8,16等):");
scanf("%d",&n);
to_change(num,n);
printf("\n");
return 0;
}
void to_change(int num,int n) //利用递归函数的实现反序输出
{
int r;
r = num % n;
if(num > 0)
to_change( num / n,n );
putchar( '0' + r);
return ;
}
输入一个字符串,计算字符串中子串出现的次字数
#include <stdio.h>
void to_change(int num,int n);
#include<stdio.h>
#include<string.h>
int fun(char *a, char *b)
{
int len_b;
int count = 0;//计数子串个数
int num = 0;//计数和b相同字符个数
char *temp = b;
len_b = strlen(b);//求b长度
while (*a != '\0')
{
if (*a == *temp)//计数入口字符和b相同
{
while ((*a == *temp) && (*a != '\0') && (*temp != '\0'))
{
num++;
a++;
temp++;
}
if (num == len_b)//退出字符个数计数时,和b长度相同则计数字串
{
count++;
}
num = 0;//重新赋值
temp = b;//重新指向字串
}
else
{
a++;
}
}
return count;
}
int main()
{
char a[100];
char b[10];
int num;
printf("Enter the main string(<=100)!\n");
scanf("%s",a);
printf("Enter the substring(<=10)!\n");
scanf("%s",b);
num = fun(a,b);
printf("The number is:%d\n",num);
return 0;
}
编写一个C函数,将”I am from shanghai ”倒置为”shanghai from am I”,即将句子中的单词位置倒置,而不改变单词内部结构.
坐忘含光 2018/7/15 10:41:48
#include <stdio.h>
#define N 50
int i=0;
void input(char c[])
{
//int i=0;
char s;
for(;(s=getchar())!='\n';i++)
{
c[i]=s;
}
c[i]='\0';
}
int main()
{
int j,k,c=0,j_c=0,jk=0,j_k=0;
char str[N],str_new[N];
printf("input a string:\n");
input(str);
j_c=i;
for(j=i;j>0;j--)
{
//printf("%c",str[j]);
if(str[j]==' ')
{
// jk++;
for(k=j+1;k<j_c;k++)
{
str_new[c++]=str[k];
}
str_new[c++]=' ';
j_c=j;
}
}
if(j==0)
{
for(k=0;k<j_c;k++)
{
str_new[c++]=str[k];
}
}
str_new[c]='\0';
for(k=0;k<i;k++)
{
printf("%c",str_new[k]);
}
printf("\n");
return 0;
}
输入一个字符串,同时输入帧头和帧尾(可以是多个字符),将该字符串中合法的帧识别出来.
#include <stdio.h>
int head_flag = 0;
int success = 0;
int my_strlen(char *str)
{
int i = 0;
while(*str != '\0')
{
i++;
str++;
}
return i;
}
char *head_add(char *str,char *head)
{
if(str == NULL ||head == NULL )
{
return NULL;
}
if(my_strlen(str) < my_strlen(head) )
{
return NULL;
}
char *temp ;
int head_len = my_strlen(head);
int head_count = 0;
while( *str != '\0' && !head_flag )
{
while(*str == *head)
{
str++;
head++;
head_count++;
if(head_count == head_len)
{
head_flag = 1;
temp = str - head_len ;
break;
}
}
str++;
}
if (head_flag)
{
//printf("%d\n",temp);
return temp;
}
else
{
printf("string illgeal");
}
}
char *tail_add(char *str,char *tail)
{
if(str == NULL ||tail == NULL )
{
return NULL;
}
if( my_strlen(str) < my_strlen(tail) )
{
return NULL;
}
int tail_len = my_strlen(tail);
int tail_count = 0;
if(head_flag)
{
while( *str != '\0' && !success)
{
while(*str == *tail)
{
str++;
tail++;
tail_count++;
if(tail_count == tail_len)
{
success = 1;
break;
}
}
str++;
}
}
if(success)
{
//printf("%d\n",str-1);
return str - 1 ;
}
else
{
printf("string illgeal");
return NULL;
}
}
int main()
{
char *str = "adsheadasitailwer";
char *head = "head";
char *tail = "tail";
char *str_start = head_add(str,head);
char *str_end = tail_add(str,tail);
printf("before:\n");
printf("%s\n",str);
printf("after:\n");
int n = str_end -str_start;
int i = 0;
// printf("%d",n);
for(i = 0; i <n ;i++)
{
printf("%c",*str_start);
str_start ++;
}
printf("\n");
return 0;
}
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