C字符操作函数大全
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:
#include <stdio.h>
#include <string.h>
int main(void)
{
?? char string[10];
?? char *str1 = "abcdefghi";
?? 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:
#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;
}
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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:
#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;
?}
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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:
#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;
?}
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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:
#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;
}
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函數名: strcpy
功? 能: 串拷貝
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;
?}
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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:
#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;
?}
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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:
#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;
?}
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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:
#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;
}
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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:
#include <stdio.h>
#include <errno.h>
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:
#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;
}
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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:
#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);
}
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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:
#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;
}
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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:
#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;
}
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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:
#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;
}
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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:
#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;
}
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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:
#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;
}
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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:
#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;
}
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函數名: strrev
功? 能: 串倒轉
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;
}
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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:
#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;
}
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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:
#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;
}
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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:
#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;
}
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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:
#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;
}
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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:
#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;
}
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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:
#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;
}
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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:
#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;
}
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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:
#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: %s\n", target);
?? return 0;
}
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