C語言字符串函數大全

轉載自http://www.360doc.com/content/08/0723/22/26860_1462024.shtml#

C語言字符串函數大全

函數名: stpcpy

功能: 拷貝一個字符串到另一個

用法: char *stpcpy(char *destin, char *source);

程序例:

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#include<stdio.h>

#include<string.h>

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int main(void)

{

??? char string[10];

??? char *str1 = "abcdefghi";

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??? stpcpy(string, str1);

??? printf("%s\n", string);

??? return 0;

}

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函數名: strcat

功能: 字符串拼接函數

用法: char *strcat(char *destin, char *source);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char destination[25];

??? char *blank = " ", *c = "C++", *Borland = "Borland";

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??? strcpy(destination, Borland);

??? strcat(destination, blank);

??? strcat(destination, c);

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??? printf("%s\n", destination);

??? return 0;

}

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函數名: strchr

功能: 在一個串中查找給定字符的第一個匹配之處

用法: char *strchr(char *str, char c);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char string[15];

??? char *ptr, c = ‘r‘;

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??? 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;

}

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函數名: strcmp

功能: 串比較

用法: int strcmp(char *str1, char *str2);

看Asic碼，str1>str2，返回值 > 0；兩串相等，返回0

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char *buf1 = "aaa", *buf2 = "bbb", *buf3 = "ccc";

??? int ptr;

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??? 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");

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??? 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");

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??? return 0;

}

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函數名: strncmpi

功能: 將一個串中的一部分與另一個串比較, 不管大小寫

用法: int strncmpi(char *str1, char *str2, unsigned maxlen);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char *buf1 = "BBB", *buf2 = "bbb";

??? int ptr;

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??? ptr = strcmpi(buf2, buf1);

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??? if (ptr > 0)

??? printf("buffer 2 is greater than buffer 1\n");

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??? if (ptr < 0)

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

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??? if (ptr == 0)

??? printf("buffer 2 equals buffer 1\n");

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??? return 0;

}

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函數名: strcpy

功能: 串拷貝

用法: char *strcpy(char *str1, char *str2);

程序例:

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#include<stdio.h>

#include<string.h>

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int main(void)

{

??? char string[10];

??? char *str1 = "abcdefghi";

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??? strcpy(string, str1);

??? printf("%s\n", string);

??? return 0;

}

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函數名: strcspn

功能: 在串中查找第一個給定字符集內容的段

用法: int strcspn(char *str1, char *str2);

程序例:

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#include<stdio.h>

#include<string.h>

#include<alloc.h>

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int main(void)

{

??? char *string1 = "1234567890";

??? char *string2 = "747DC8";

??? int length;

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??? length = strcspn(string1, string2);

??? printf("Character where strings intersect is at position %d\n", length);

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??? return 0;

}

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函數名: strdup

功能: 將串拷貝到新建的位置處

用法: char *strdup(char *str);

程序例:

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#include<stdio.h>

#include<string.h>

#include<alloc.h>

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int main(void)

{

??? char *dup_str, *string = "abcde";

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??? dup_str = strdup(string);

??? printf("%s\n", dup_str);

??? free(dup_str);

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??? return 0;

}

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函數名: stricmp

功能: 以大小寫不敏感方式比較兩個串

用法: int stricmp(char *str1, char *str2);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char *buf1 = "BBB", *buf2 = "bbb";

??? int ptr;

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??? ptr = stricmp(buf2, buf1);

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??? if (ptr > 0)

??? printf("buffer 2 is greater than buffer 1\n");

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??? if (ptr < 0)

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

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??? if (ptr == 0)

??? printf("buffer 2 equals buffer 1\n");

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??? return 0;

}

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函數名: strerror

功能: 返回指向錯誤信息字符串的指針

用法: char *strerror(int errnum);

程序例:

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#include<stdio.h>

#include<errno.h>

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int main(void)

{

??? char *buffer;

??? buffer = strerror(errno);

??? printf("Error: %s\n", buffer);

??? return 0;

}

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函數名: strcmpi

功能: 將一個串與另一個比較, 不管大小寫

用法: int strcmpi(char *str1, char *str2);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char *buf1 = "BBB", *buf2 = "bbb";

??? int ptr;

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??? ptr = strcmpi(buf2, buf1);

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??? if (ptr > 0)

??? printf("buffer 2 is greater than buffer 1\n");

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??? if (ptr < 0)

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

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??? if (ptr == 0)

??? printf("buffer 2 equals buffer 1\n");

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??? return 0;

}

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函數名: strncmp

功能: 串比較

用法: int strncmp(char *str1, char *str2, int maxlen);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

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{

??? char *buf1 = "aaabbb", *buf2 = "bbbccc", *buf3 = "ccc";

??? int ptr;

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??? 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");

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??? 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");

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??? return(0);

}

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函數名: strncmpi

功能: 把串中的一部分與另一串中的一部分比較, 不管大小寫

用法: int strncmpi(char *str1, char *str2);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char *buf1 = "BBBccc", *buf2 = "bbbccc";

??? int ptr;

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??? ptr = strncmpi(buf2,buf1,3);

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??? if (ptr > 0)

??? printf("buffer 2 is greater than buffer 1\n");

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??? if (ptr < 0)

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

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??? if (ptr == 0)

??? printf("buffer 2 equals buffer 1\n");

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??? return 0;

}

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函數名: strncpy

功能: 串拷貝

用法: char *strncpy(char *destin, char *source, int maxlen);

程序例:

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#include<stdio.h>

#include<string.h>

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int main(void)

{

??? char string[10];

??? char *str1 = "abcdefghi";

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??? strncpy(string, str1, 3);

??? string[3] = ‘\0‘;

??? printf("%s\n", string);

??? return 0;

}

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函數名: strnicmp

功能: 不注重大小寫地比較兩個串

用法: int strnicmp(char *str1, char *str2, unsigned maxlen);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char *buf1 = "BBBccc", *buf2 = "bbbccc";

??? int ptr;

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??? ptr = strnicmp(buf2, buf1, 3);

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??? if (ptr > 0)

??? printf("buffer 2 is greater than buffer 1\n");

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??? if (ptr < 0)

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

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??? if (ptr == 0)

??? printf("buffer 2 equals buffer 1\n");

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??? return 0;

}

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函數名: strnset

功能: 將一個串中的所有字符都設為指定字符

用法: char *strnset(char *str, char ch, unsigned n);

程序例:

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#include<stdio.h>

#include<string.h>

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int main(void)

{

??? char *string = "abcdefghijklmnopqrstuvwxyz";

??? char letter = ‘x‘;

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??? printf("string before strnset: %s\n", string);

??? strnset(string, letter, 13);

??? printf("string after? strnset: %s\n", string);

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??? return 0;

}

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函數名: strpbrk

功能: 在串中查找給定字符集中的字符

用法: char *strpbrk(char *str1, char *str2);

程序例:

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#include<stdio.h>

#include<string.h>

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int main(void)

{

??? char *string1 = "abcdefghijklmnopqrstuvwxyz";

??? char *string2 = "onm";

??? char *ptr;

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??? ptr = strpbrk(string1, string2);

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??? if (ptr)

??? printf("strpbrk found first character: %c\n", *ptr);

??? else

??? printf("strpbrk didn‘t find character in set\n");

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??? return 0;

}

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函數名: strrchr

功能: 在串中查找指定字符的最后一個出現

用法: char *strrchr(char *str, char c);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char string[15];

??? char *ptr, c = ‘r‘;

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??? 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;

}

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函數名: strrev

功能: 串倒轉

用法: char *strrev(char *str);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char *forward = "string";

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??? printf("Before strrev(): %s\n", forward);

??? strrev(forward);

??? printf("After strrev():? %s\n", forward);

??? return 0;

}

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函數名: strset

功能: 將一個串中的所有字符都設為指定字符

用法: char *strset(char *str, char c);

程序例:

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#include<stdio.h>

#include<string.h>

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int main(void)

{

??? char string[10] = "123456789";

??? char symbol = ‘c‘;

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??? printf("Before strset(): %s\n", string);

??? strset(string, symbol);

??? printf("After strset():? %s\n", string);

??? return 0;

}

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函數名: strspn

功能: 在串中查找指定字符集的子集的第一次出現

用法: int strspn(char *str1, char *str2);

程序例:

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#include<stdio.h>

#include<string.h>

#include<alloc.h>

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int main(void)

{

??? char *string1 = "1234567890";

??? char *string2 = "123DC8";

??? int length;

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??? length = strspn(string1, string2);

??? printf("Character where strings differ is at position %d\n", length);

??? return 0;

}

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函數名: strstr

功能: 在串中查找指定字符串的第一次出現

用法: char *strstr(char *str1, char *str2);

程序例:

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#include<stdio.h>

#include<string.h>

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int main(void)

{

??? char *str1 = "Borland International", *str2 = "nation", *ptr;

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??? ptr = strstr(str1, str2);

??? printf("The substring is: %s\n", ptr);

??? return 0;

}

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函數名: strtod

功能: 將字符串轉換為double型值

用法: double strtod(char *str, char **endptr);

程序例:

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#include<stdio.h>

#include<stdlib.h>

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int main(void)

{

??? char input[80], *endptr;

??? double value;

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??? 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;

}

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函數名: strtok

功能: 查找由在第二個串中指定的分界符分隔開的單詞

用法: char *strtok(char *str1, char *str2);

程序例:

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#include<string.h>

#include<stdio.h>

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int main(void)

{

??? char input[16] = "abc,d";

??? char *p;

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??? /* strtok places a NULL terminator

??? ?in front of the token, if found */

??? p = strtok(input, ",");

??? if (p) printf("%s\n", p);

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??? /* 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;

}

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函數名: strtol

功能: 將串轉換為長整數

用法: long strtol(char *str, char **endptr, int base);

程序例:

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#include<stdlib.h>

#include<stdio.h>

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int main(void)

{

??? char *string = "87654321", *endptr;

??? long lnumber;

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??? /* strtol converts string to long integer? */

??? lnumber = strtol(string, &endptr, 10);

??? printf("string = %s? long = %ld\n", string, lnumber);

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??? return 0;

}

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函數名: strupr

功能: 將串中的小寫字母轉換為大寫字母

用法: char *strupr(char *str);

程序例:

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#include<stdio.h>

#include<string.h>

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int main(void)

{

??? char *string = "abcdefghijklmnopqrstuvwxyz", *ptr;

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??? /* converts string to upper case characters */

??? ptr = strupr(string);

??? printf("%s\n", ptr);

??? return 0;

}

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函數名: swab

功能: 交換字節

用法: void swab (char *from, char *to, int nbytes);

程序例:

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#include<stdlib.h>

#include<stdio.h>

#include<string.h>

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char source[15] = "rFna koBlrna d";

char target[15];

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int main(void)

{

??? swab(source, target, strlen(source));

??? printf("This is target: %s\n", target);

??? return 0;

}