linux c 字符处理函数

本文精选了C语言中常见的字符串处理函数,并提供了详细的使用说明及示例代码,包括字符串拷贝、拼接、查找等功能。

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函数主要包括

1,字符测试函数

2,字符转换函数

3,字符串比较函数

4,字符串复制函数

5,字符串清理与填充函数

6,字符串查找函数

7,字符串连接与分割函数

以下只介绍了常用的字符函数

更多可参考

linux c函数参考手册(经典)

                                   http://net.pku.edu.cn/~yhf/linux_c/

参考手册 word版下载  http://wenku.baidu.com/view/af9df856ad02de80d4d840d8.html


其他博文参考

http://wenku.baidu.com/view/202a131fc5da50e2524d7f78.html

http://leasor.blog.163.com/blog/static/4481406620096162417833/



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("%sn", 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("%sn", 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: %dn", c, ptr-string);
     else
        printf("The character was not foundn");
     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 1n");
     else
        printf("buffer 2 is less than buffer 1n");

     ptr = strcmp(buf2, buf3);
     if (ptr > 0)
        printf("buffer 2 is greater than buffer 3n");
     else
        printf("buffer 2 is less than buffer 3n");

     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 1n");

    if (ptr < 0)
       printf("buffer 2 is less than buffer 1n");

    if (ptr == 0)
       printf("buffer 2 equals buffer 1n");

    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("%sn", 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 %dn", 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("%sn", 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 1n");

    if (ptr < 0)
       printf("buffer 2 is less than buffer 1n");

    if (ptr == 0)
       printf("buffer 2 equals buffer 1n");

    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: %sn", 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 1n");

    if (ptr < 0)
       printf("buffer 2 is less than buffer 1n");

    if (ptr == 0)
       printf("buffer 2 equals buffer 1n");

    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 1n");
    else
       printf("buffer 2 is less than buffer 1n");

    ptr = strncmp(buf2,buf3,3);
    if (ptr > 0)
       printf("buffer 2 is greater than buffer 3n");
    else
       printf("buffer 2 is less than buffer 3n");

    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 1n");

    if (ptr < 0)
       printf("buffer 2 is less than buffer 1n");

    if (ptr == 0)
       printf("buffer 2 equals buffer 1n");

    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] = '';
    printf("%sn", 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 1n");

    if (ptr < 0)
       printf("buffer 2 is less than buffer 1n");

    if (ptr == 0)
       printf("buffer 2 equals buffer 1n");

    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: %sn", string);
    strnset(string, letter, 13);
    printf("string after   strnset: %sn", 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: %cn", *ptr);
    else
       printf("strpbrk didn't find character in setn");

    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: %dn", c, ptr-string);
    else
       printf("The character was not foundn");
    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(): %sn", forward);
    strrev(forward);
    printf("After strrev():   %sn", 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(): %sn", string);
    strset(string, symbol);
    printf("After strset():   %sn", 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 %dn", 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: %sn", 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 %lfn", 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;

   
    p = strtok(input, ",");
    if (p)    printf("%sn", p);

   
    p = strtok(NULL, ",");
    if (p)    printf("%sn", 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;

   
    lnumber = strtol(string, &endptr, 10);
    printf("string = %s   long = %ldn", 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;

   
    ptr = strupr(string);
    printf("%sn", 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];

int main(void)
{
    swab(source, target, strlen(source));
    printf("This is target: %sn", target);
    return 0;
}


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