C语言字符串函数大全

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C语言字符串函数大全

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<stdio.h>
#include<string.h>
 
int main(void)
{
   char
string[10];
   char
*str1 ="abcdefghi";
 
   stpcpy(string, str1);
   printf("%s\n",
string);
   return
0;
}
 
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<string.h>
#include<stdio.h>
 
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;
}
 
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<string.h>
#include<stdio.h>
 
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;
}
 
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<string.h>
#include<stdio.h>
 
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;
}
 
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<string.h>
#include<stdio.h>
 
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: strcpy
功能:串拷贝
用法:char
*strcpy(char *str1,
char *str2);
程序例:
 
#include<stdio.h>
#include<string.h>
 
int main(void)
{
   char
string[10];
   char
*str1 ="abcdefghi";
 
   strcpy(string, str1);
   printf("%s\n",
string);
   return
0;
}
 
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<stdio.h>
#include<string.h>
#include<alloc.h>
 
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;
}
 
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<stdio.h>
#include<string.h>
#include<alloc.h>
 
int main(void)
{
   char
*dup_str, *string ="abcde";
 
   dup_str = strdup(string);
   printf("%s\n",
dup_str);
   free(dup_str);
 
   return
0;
}
 
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<string.h>
#include<stdio.h>
 
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;
}
 
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<stdio.h>
#include<errno.h>
 
int main(void)
{
   char
*buffer;
   buffer = strerror(errno);
   printf("Error: %s\n",
buffer);
   return
0;
}
 
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<string.h>
#include<stdio.h>
 
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<string.h>
#include<stdio.h>
 
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);
}
 
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<string.h>
#include<stdio.h>
 
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;
}
 
函数名: strncpy
功能:串拷贝
用法:char
*strncpy(char *destin,
char *source,int
maxlen);
程序例:
 
#include<stdio.h>
#include<string.h>
 
int main(void)
{
   char
string[10];
   char
*str1 ="abcdefghi";
 
   strncpy(string, str1, 3);
   string[3] =
‘\0‘;
   printf("%s\n",
string);
   return
0;
}
 
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<string.h>
#include<stdio.h>
 
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;
}
 
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<stdio.h>
#include<string.h>
 
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;
}
 
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<stdio.h>
#include<string.h>
 
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;
}
 
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<string.h>
#include<stdio.h>
 
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;
}
 
函数名: strrev
功能:串倒转
用法:char
*strrev(char *str);
程序例:
 
#include<string.h>
#include<stdio.h>
 
int main(void)
{
   char
*forward ="string";
 
   printf("Before strrev(): %s\n",
forward);
   strrev(forward);
   printf("After strrev(): %s\n",
forward);
   return
0;
}
 
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<stdio.h>
#include<string.h>
 
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;
}
 
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<stdio.h>
#include<string.h>
#include<alloc.h>
 
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;
}
 
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<stdio.h>
#include<string.h>
 
int main(void)
{
   char
*str1 ="Borland International", *str2 ="nation",
*ptr;
 
   ptr = strstr(str1, str2);
   printf("The substring is: %s\n",
ptr);
   return
0;
}
 
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<stdio.h>
#include<stdlib.h>
 
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;
}
 
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<string.h>
#include<stdio.h>
 
int main(void)
{
   char
input[16] ="abc,d";
   char
*p;
 
   /* strtok places a NULL terminator
    in front of the token, if found */
   p = strtok(input,
",");
   if
(p) printf("%s\n", p);
 
   /* A second call to strtok using
a NULL
    as the first parameter returns a pointer

    to the character following the token 
*/
   p = strtok(NULL,
",");
   if
(p) printf("%s\n", p);
   return
0;
}
 
函数名: strtol
功能:将串转换为长整数
用法:long
strtol(char *str,
char **endptr,int
base);
程序例:
 
#include<stdlib.h>
#include<stdio.h>
 
int main(void)
{
   char
*string ="87654321", *endptr;
   long
lnumber;
 
   /* strtol converts string to
long integer */
   lnumber = strtol(string, &endptr, 10);
   printf("string = %s long
= %ld\n", string, lnumber);
 
   return
0;
}
 
函数名: strupr
功能:将串中的小写字母转换为大写字母
用法:char
*strupr(char *str);
程序例:
 
#include<stdio.h>
#include<string.h>
 
int main(void)
{
   char
*string ="abcdefghijklmnopqrstuvwxyz", *ptr;
 
   /* converts string to upper
case characters */
   ptr = strupr(string);
   printf("%s\n",
ptr);
   return
0;
}
 
函数名: swab
功能:交换字节
用法:void
swab (char *from,
char *to,int
nbytes);
程序例:
 
#include<stdlib.h>
#include<stdio.h>
#include<string.h>
 
char source[15] ="rFna
koBlrna d";
char target[15];
 
intmain(void)
{
   swab(source,
target,strlen(source));
   printf("This
is target: %s\n", target);
   return
0;
}