#include<stdio.h>
#include<string.h>
#include<stdlib.h>
void change(char *str)
{
char *begin;
char *c = (char *)malloc(sizeof(char) * 32);
int i,length = strlen(str);
begin = str;
str += length - 1;
while(str >= begin)
{
*c++ = *str--;
}
*c = '\0';
printf("%s\n",c - strlen(begin));
}
void main()
{
char *b = (char *)malloc(sizeof(char) * 32);
if(NULL == b)
{
printf("malloc failure!\n");
return -1;
}
printf("输入一个字符串：\n");
scanf("%s",b);
change(b);
}
2、#include<stdio.h>
#include<string.h>
#include<stdlib.h>
void change(int a,char *s,int n)
{
int i,j=0;
for(i=0;i<32;i++)
{
s[i]=a%n;
a = a/n;
if(a == 0)
{
break;
}
}
for(;i>=0;i--,j=0)
{
if(s[i]>=10)
{
switch(s[i])
{
case 1:s[i]='A';printf("%c",s[i]);j++;break;
case 2:s[i]='B';printf("%c",s[i]);j++;break;
case 3:s[i]='C';printf("%c",s[i]);j++;break;
case 4:s[i]='D';printf("%c",s[i]);j++;break;
case 5:s[i]='E';printf("%c",s[i]);j++;break;
case 6:s[i]='F';printf("%c",s[i]);j++;break;
default :printf("大于16进制只用数字表示\n");break;
}
}
if((i=i-j)>=0)
{
printf("%d",s[i]);
}
}
}
void main()
{
int a,n;
char *s=(char*)malloc(sizeof(char)*64);
printf("输入一个整数\n");
scanf("%d",&a);
printf("输入转换成几进制数\n");
scanf("%d",&n);
change(a,s,n);
printf("\n");
}
//3、输入一个字符串,计算字符串中子串出现的次字数
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main()
{
int i=0,count = 1;
char str[1000] = {0};
char ch, *p = str ;
while((ch = getchar()) != '\n')
{
str[i] = ch;
i ++;
}
while(*p != '\0') //将空格计数
{
if(*p == ' ')
{
count += 1;
}
p++;
}
printf("字符串中子串个数：%d \n",count);
}
//4.题目: 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.
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
int main()
{
int i=0;
char str[1000] = {0};
char ch, *p = str ;
while((ch = getchar()) != '\n')
{
str[i] = ch;
i ++;
}
while(*p != '\0') //将空格替换为\0
{
if(*p == ' ')
{
*p = '\0';
}
p++;
}
while(p != str) //指针p向前移动，打印每个单词
{
p --;
if(*p == '\0')
{
printf("%s ", p+1);
}
}
printf("%s",p);
ptintf("\n");
}
5、#include <stdio.h>
int mystrlen(const char *str)
{
int length = 0;
while (*str++)
{
length++;
}
return length;
}
char* mystrstr(const char *str, const char *sub) //寻找字串函数
{
int n = 0;
if (sub != NULL)
{
while (*str)
{
for (n = 0; (*(str + n) == *(sub + n)); n++)
{
if (*(sub + n + 1) == '\0')
{
return (char *)str;
}
}
str++;
}
return NULL;
}
else
{
return (char *)str;
}
}
void IdenStr(char *str, char *outbuf)
{
int count = 0;
char *p1 = NULL;
char *p2 = NULL;
char *h = "head"; //祯头，桢尾
char *t = "tail";
int tlen = mystrlen(t);
p1 = mystrstr(str, h); //找到head,tail的位置
p2 = mystrstr(str, t);
p2 += tlen;
count = p2 - p1; //求出head,tail之间有多少字符
while (count)
{
*outbuf++ = *p1++; //全部存入outbuf中
count--;
}
}
int main()
{
char str[100] = {0};
char outbuf[100] = {0}; //存放处理完的字符串
printf ("Please input a string (head...tail): \n");
scanf ("%s", str);
IdenStr(str, outbuf);
printf ("The result is %s\n", outbuf); //打印结果
return 0;
}