Stringh函数详解.docx
《Stringh函数详解.docx》由会员分享,可在线阅读,更多相关《Stringh函数详解.docx(15页珍藏版)》请在冰豆网上搜索。
Stringh函数详解
string.h-string.h文件中函数的详细用法
下面为string.h文件中函数的详细用法,附加实例:
1、strcpy
函数名:
stpcpy
功 能:
拷贝一个字符串到另一个
用 法:
char *stpcpy(char *destin, char *source);
程序例:
#include
#include
int main(void)
{
char string[10];
char *str1 = "abcdefghi";
stpcpy(string, str1);
printf("%s\n", string);
return 0;
}
2、strcat
函数名:
strcat
功 能:
字符串拼接函数
用 法:
char *strcat(char *destin, char *source);
程序例:
#include
#include
int main(void)
{
char destination[25];
char *blank = " ", *c = "C++", *Borland = "Borland";
strcpy(destination, Borland);
strcat(destination, blank);
strcat(destination, c);
printf("%s\n", destination);
return 0;
}
3、strchr
函数名:
strchr
功 能:
在一个串中查找给定字符的第一个匹配之处\
用 法:
char *strchr(char *str, char c);
程序例:
#include
#include
int main(void)
{
char string[15];
char *ptr, c = 'r';
strcpy(string, "This is a string");
ptr = strchr(string, c);
if (ptr)
printf("The character %c is at position:
%d\n", c, ptr-string);
else
printf("The character was not found\n");
return 0;
}
4、strcmp
函数名:
strcmp
功 能:
串比较
用 法:
int strcmp(char *str1, char *str2);
看Asic码,str1>str2,返回值 > 0;两串相等,返回0
程序例:
#include
#include
int main(void)
{
char *buf1 = "aaa", *buf2 = "bbb", *buf3 = "ccc";
int ptr;
ptr = strcmp(buf2, buf1);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
else
printf("buffer 2 is less than buffer 1\n");
ptr = strcmp(buf2, buf3);
if (ptr > 0)
printf("buffer 2 is greater than buffer 3\n");
else
printf("buffer 2 is less than buffer 3\n");
return 0;
}
5、strncmpi
函数名:
strncmpi
功 能:
将一个串中的一部分与另一个串比较, 不管大小写
用 法:
int strncmpi(char *str1, char *str2, unsigned maxlen);
程序例:
#include
#include
int main(void)
{
char *buf1 = "BBB", *buf2 = "bbb";
int ptr;
ptr = strcmpi(buf2, buf1);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
if (ptr < 0)
printf("buffer 2 is less than buffer 1\n");
if (ptr == 0)
printf("buffer 2 equals buffer 1\n");
return 0;
}
6、strcpy
函数名:
strcpy
功 能:
串拷贝
用 法:
char *strcpy(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char string[10];
char *str1 = "abcdefghi";
strcpy(string, str1);
printf("%s\n", string);
return 0;
}
7、strcspn
函数名:
strcspn
功 能:
在串中查找第一个给定字符集内容的段
用 法:
int strcspn(char *str1, char *str2);
程序例:
#include
#include
#include
int main(void)
{
char *string1 = "1234567890";
char *string2 = "747DC8";
int length;
length = strcspn(string1, string2);
printf("Character where strings intersect is at position %d\n", length);
return 0;
}
8、strdup
函数名:
strdup
功 能:
将串拷贝到新建的位置处
用 法:
char *strdup(char *str);
程序例:
#include
#include
#include
int main(void)
{
char *dup_str, *string = "abcde";
dup_str = strdup(string);
printf("%s\n", dup_str);
free(dup_str);
return 0;
}
9、stricmp
函数名:
stricmp
功 能:
以大小写不敏感方式比较两个串
用 法:
int stricmp(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *buf1 = "BBB", *buf2 = "bbb";
int ptr;
ptr = stricmp(buf2, buf1);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
if (ptr < 0)
printf("buffer 2 is less than buffer 1\n");
if (ptr == 0)
printf("buffer 2 equals buffer 1\n");
return 0;
}
10、strerror
函数名:
strerror
功 能:
返回指向错误信息字符串的指针
用 法:
char *strerror(int errnum);
程序例:
#include
#include
int main(void)
{
char *buffer;
buffer = strerror(errno);
printf("Error:
%s\n", buffer);
return 0;
}
11、strcmpi
函数名:
strcmpi
功 能:
将一个串与另一个比较, 不管大小写
用 法:
int strcmpi(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *buf1 = "BBB", *buf2 = "bbb";
int ptr;
ptr = strcmpi(buf2, buf1);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
if (ptr < 0)
printf("buffer 2 is less than buffer 1\n");
if (ptr == 0)
printf("buffer 2 equals buffer 1\n");
return 0;
}
函数名:
strncmp
功 能:
串比较
用 法:
int strncmp(char *str1, char *str2, int maxlen);
程序例:
#include
#include
int main(void)
{
char *buf1 = "aaabbb", *buf2 = "bbbccc", *buf3 = "ccc";
int ptr;
ptr = strncmp(buf2,buf1,3);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
else
printf("buffer 2 is less than buffer 1\n");
ptr = strncmp(buf2,buf3,3);
if (ptr > 0)
printf("buffer 2 is greater than buffer 3\n");
else
printf("buffer 2 is less than buffer 3\n");
return(0);
}
12、strncmpi
函数名:
strncmpi
功 能:
把串中的一部分与另一串中的一部分比较, 不管大小写
用 法:
int strncmpi(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *buf1 = "BBBccc", *buf2 = "bbbccc";
int ptr;
ptr = strncmpi(buf2,buf1,3);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
if (ptr < 0)
printf("buffer 2 is less than buffer 1\n");
if (ptr == 0)
printf("buffer 2 equals buffer 1\n");
return 0;
}
13、strncpy
函数名:
strncpy
功 能:
串拷贝
用 法:
char *strncpy(char *destin, char *source, int maxlen);
程序例:
#include
#include
int main(void)
{
char string[10];
char *str1 = "abcdefghi";
strncpy(string, str1, 3);
string[3] = '\0';
printf("%s\n", string);
return 0;
}
14、strnicmp
函数名:
strnicmp
功 能:
不注重大小写地比较两个串
用 法:
int strnicmp(char *str1, char *str2, unsigned maxlen);
程序例:
#include
#include
int main(void)
{
char *buf1 = "BBBccc", *buf2 = "bbbccc";
int ptr;
ptr = strnicmp(buf2, buf1, 3);
if (ptr > 0)
printf("buffer 2 is greater than buffer 1\n");
if (ptr < 0)
printf("buffer 2 is less than buffer 1\n");
if (ptr == 0)
printf("buffer 2 equals buffer 1\n");
return 0;
}
15、strnset
函数名:
strnset
功 能:
将一个串中的所有字符都设为指定字符
用 法:
char *strnset(char *str, char ch, unsigned n);
程序例:
#include
#include
int main(void)
{
char *string = "abcdefghijklmnopqrstuvwxyz";
char letter = 'x';
printf("string before strnset:
%s\n", string);
strnset(string, letter, 13);
printf("string after strnset:
%s\n", string);
return 0;
}
16、strpbrk
函数名:
strpbrk
功 能:
在串中查找给定字符集中的字符
用 法:
char *strpbrk(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *string1 = "abcdefghijklmnopqrstuvwxyz";
char *string2 = "onm";
char *ptr;
ptr = strpbrk(string1, string2);
if (ptr)
printf("strpbrk found first character:
%c\n", *ptr);
else
printf("strpbrk didn't find character in set\n");
return 0;
}
17、strrchr
函数名:
strrchr
功 能:
在串中查找指定字符的最后一个出现
用 法:
char *strrchr(char *str, char c);
程序例:
#include
#include
int main(void)
{
char string[15];
char *ptr, c = 'r';
strcpy(string, "This is a string");
ptr = strrchr(string, c);
if (ptr)
printf("The character %c is at position:
%d\n", c, ptr-string);
else
printf("The character was not found\n");
return 0;
}
18、strrev
函数名:
strrev
功 能:
串倒转
用 法:
char *strrev(char *str);
程序例:
#include
#include
int main(void)
{
char *forward = "string";
printf("Before strrev():
%s\n", forward);
strrev(forward);
printf("After strrev():
%s\n", forward);
return 0;
}
19、strset
函数名:
strset
功 能:
将一个串中的所有字符都设为指定字符
用 法:
char *strset(char *str, char c);
程序例:
#include
#include
int main(void)
{
char string[10] = "123456789";
char symbol = 'c';
printf("Before strset():
%s\n", string);
strset(string, symbol);
printf("After strset():
%s\n", string);
return 0;
}
20、strspn
函数名:
strspn
功 能:
在串中查找指定字符集的子集的第一次出现
用 法:
int strspn(char *str1, char *str2);
程序例:
#include
#include
#include
int main(void)
{
char *string1 = "1234567890";
char *string2 = "123DC8";
int length;
length = strspn(string1, string2);
printf("Character where strings differ is at position %d\n", length);
return 0;
}
21、strstr
函数名:
strstr
功 能:
在串中查找指定字符串的第一次出现
用 法:
char *strstr(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char *str1 = "Borland International", *str2 = "nation", *ptr;
ptr = strstr(str1, str2);
printf("The substring is:
%s\n", ptr);
return 0;
}
22、strtod
函数名:
strtod
功 能:
将字符串转换为double型值
用 法:
double strtod(char *str, char **endptr);
程序例:
#include
#include
int main(void)
{
char input[80], *endptr;
double value;
printf("Enter a floating point number:
");
gets(input);
value = strtod(input, &endptr);
printf("The string is %s the number is %lf\n", input, value);
return 0;
}
23、strtok
函数名:
strtok
功 能:
查找由在第二个串中指定的分界符分隔开的单词
用 法:
char *strtok(char *str1, char *str2);
程序例:
#include
#include
int main(void)
{
char input[16] = "abc,d";