Vuser中常用的C语言函数

strchr函数与strrchr函数查找指定字符（仅能判断字符，不能是字符串）在字符串中的位置

 1 Action()
 2 {
 3 //    strchr函数用于查找指定字符在一个字符串中第1次出现的位置，然后返回指向该位置的指针；
 4 //    strrchr函数用户查找指定字符在一个字符串中最后1次出现的位置，然后返回指向该位置的指针。
 5 //    语法结构
 6 //        char *strchr(const char *string,int c);
 7 //        char *strrchr(const char *string,int c);
 8     
 9     
10     char *string = "I'm a young soul in this very strange world";
11     char *first_a, *last_a;
12     
13     first_a = (char *)strchr(string, 'a');
14     lr_output_message("The first occurrence of a: %s", first_a);
15     
16     last_a = (char *)strrchr(string, 'a');
17     lr_output_message("The last occurrence of a: %s", last_a);
18     
19     return 0;
20 }
21 -----------------------------------------------------------------------------------
22 Running Vuser...
23 Starting iteration 1.
24 Maximum number of concurrent connections per server: 6      [MsgId: MMSG-26989]
25 Starting action Action.
26 Action.c(14): The first occurrence of a: a young soul in this very strange world
27 Action.c(17): The last occurrence of a: ange world
28 Ending action Action.
29 Ending iteration 1.
30 Ending Vuser...

strcpy函数与strncpy函数复制字符串

 1 Action()
 2 {
 3 //    strcpy函数是把一个字符串复制到另一个字符串中；
 4 //    strncpy函数是把一个字符串中的指定长度复制到另一个字符串中，如果指定长度超过了字符串长度，则会复制整个字符串。
 5 //    语法结构
 6 //        strcpy:    char *strcpy(char *dest, const char *source);
 7 //        strncpy:    char *strncpy(char *dest,const char *source, size_t n);
 8 //    参数dest是目标字符串，source是源字符串，n是要复制的长度。
 9         
10     
11     char test[50];
12     char ntest[50];
13     strcpy(test, "Copies one string to another.");
14     lr_output_message("%s", test);
15     
16     strncpy(ntest, "Copies the first n characters of one string to another?", 30);
17     lr_output_message("%s", ntest);
18         
19     return 0;
20 }
21 
22 ----------------------------------------------------------------------------------
23 Running Vuser...
24 Starting iteration 1.
25 Maximum number of concurrent connections per server: 6      [MsgId: MMSG-26989]
26 Starting action Action.
27 Action.c(14): Copies one string to another.
28 Action.c(17): Copies the first n characters 
29 Ending action Action.
30 Ending iteration 1.
31 Ending Vuser...

strcmp函数与stricmp函数用于按照字母表顺序来比较两个字符串的大小

 1 Action()
 2 {
 3 //    strcmp函数与stricmp函数用于按照字母表顺序来比较两个字符串的大小，前者比较时区分字符串的大小写，后者比较时不区分字符串的大小写
 4 //    语法结构
 5 //        strcmp:    int strcmp(const char *string1, const char *string2);
 6 //        stricmp:    int stricmp(const char *string1, const char *string2);
 7         
 8     int result;
 9     char tmp[20];
10     char string1[] = "He is a test";
11     char string2[] = "He is a TEST";
12     
13 //    strcmp区分大小写
14     result = strcmp(string1, string2);
15     if(result > 0)strcpy(tmp, "greater than");
16     else if(result < 0)strcpy(tmp, "less than");
17     else strcpy(tmp, "equal to");
18     
19     lr_output_message("strcmp: String1 is %s string2", tmp);
20     
21 //    stricmp不区分大小写
22     result = stricmp(string1, string2);
23     if(result > 0)strcpy(tmp, "greater than");
24     else if(result < 0)strcpy(tmp, "less than");
25     else strcpy(tmp, "equal to");
26     
27     lr_output_message("stricmp: String1 is %s string2", tmp);
28     
29     return 0;
30 }
31 
32 ---------------------------------------------------------------------------------------
33 Running Vuser...
34 Starting iteration 1.
35 Maximum number of concurrent connections per server: 6      [MsgId: MMSG-26989]
36 Starting action Action.
37 Action.c(19): strcmp: String1 is greater than string2
38 Action.c(27): stricmp: String1 is equal to string2
39 Ending action Action.
40 Ending iteration 1.
41 Ending Vuser...

strcat函数与strncat函数都是字符串连接函数

 1 Action()
 2 {
 3 //    strcat函数与strncat函数都是字符串连接函数；
 4 //    strcat：把一个字符串全部内容复制到另一个字符串后面；
 5 //    strncat：把一个字符串的指定长度复制到另一个字符串的后面，如果指定长度超过了字符串的长度，则会复制整个字符串。
 6 //    语法结构：
 7 //        strcat:    char *strcat(char *to_string,const char *from_string);
 8 //        strncat:    char *strncat(char *to_string,const char *from_string, size_t n);
 9     
10     char str1[] = "This is ";
11     char str2[] = "a ";
12     char str3[] = "strcat&strncat ";
13     char str4[] = "test!";
14     lr_output_message("The str1 is: %s", str1);
15     
16     strcat(str1, str2);
17     lr_output_message("The str1 is: %s", str1);
18     
19     strncat(str1, str3, 100);
20     lr_output_message("The str1 is: %s", str1);
21     
22     strcat(str1, str4, 5);
23     lr_output_message("The str1 is: %s", str1);
24     
25     return 0;
26 }
27 
28 -------------------------------------------------------------------------
29 Starting iteration 1.
30 Maximum number of concurrent connections per server: 6      [MsgId: MMSG-26989]
31 Starting action Action.
32 Action.c(14): The str1 is: This is 
33 Action.c(17): The str1 is: This is a 
34 Action.c(20): The str1 is: This is a strcat&strncat 
35 Action.c(23): The str1 is: This is a strcat&strncat test!
36 Ending action Action.

sprintf函数：把一个字符串格式化后输入到另一个字符串中，然后返回写入的字符数量

 1 Action()
 2 {
 3 //    sprintf函数：把一个字符串格式化后输入到另一个字符串中，然后返回写入的字符数量
 4 //    语法结构：
 5 //        sprintf:    int sprintf(char *string,const char *format_string[,args]);
 6     
 7     char test[30];
 8     int a=2,b=8;
 9     sprintf(test, "Add Test: a=%d,b%d,a+b=%d.", a, b, a+b);    // 字符串中的“”是字符串结束符。
10     lr_output_message(test);
11     
12     return 0;
13 }
14 
15 -------------------------------------------------------------------------
16 Starting iteration 1.
17 Maximum number of concurrent connections per server: 6      [MsgId: MMSG-26989]
18 Starting action Action.
19 Action.c(10): Add Test: a=2,b8,a+b=10.
20 Ending action Action.
21 Ending iteration 1.

strlwr函数：把一个字符串全部变小写；
strupr函数：把一个字符串全部变大写；

 1 Action()
 2 {
 3 //    strlwr函数：把一个字符串全部变小写；
 4 //    strupr函数：把一个字符串全部变大写；
 5 //    语法结构：
 6 //        strlwr:    char *strlwr(char *string);
 7 //        strupr:    char *strupr(char *string);
 8     
 9     char str[] = "ThIS is A tEst.";
10     char *lowerstr, *upperstr;
11     
12     lowerstr = (char *)strlwr(str);
13     lr_output_message("lowerstr=%s", lowerstr);
14     lr_output_message("str=%s", str);
15     
16     upperstr = (char *)strupr(str);
17     lr_output_message("upperstr=%s", upperstr);
18     lr_output_message("str=%s", str);
19         
20     return 0;
21 }
22 
23 -------------------------------------------------------------------------
24 Starting iteration 1.
25 Maximum number of concurrent connections per server: 6      [MsgId: MMSG-26989]
26 Starting action Action.
27 Action.c(13): lowerstr=this is a test.
28 Action.c(14): str=this is a test.
29 Action.c(17): upperstr=THIS IS A TEST.
30 Action.c(18): str=THIS IS A TEST.
31 Ending action Action.
32 Ending iteration 1.

atoi函数：把一个字符串转为整数；

itoa函数：把整数转为字符串；

 1 Action()
 2 {
 3 //    atoi函数：把一个字符串转为整数；
 4 //    itoa函数：把整数转为字符串；
 5 //    语法结构：
 6 //        atoi:    int atoi(const char *string);
 7 //        itoa:    int itoa(int value,char *string,int radix);
 8 //            参数value是要转换的整数，string是用例保存转换结果的字符串，radix是转换时的进制。
 9     
10     int j, i;
11     char *s = "aaa 111 bbb 222";
12     char str_int[10], str_hex[10];
13     
14     j = atoi(s);
15     lr_output_message("Result:%d", j);
16     
17     s = "111 bbb 222";
18     j = atoi(s);
19     lr_output_message("Result:%d", j);
20 
21 
22     i=56;
23     itoa(i, str_int, 10);
24     lr_output_message("New file name %s", str_int);
25     
26     itoa(i, str_hex, 16);
27     lr_output_message("New file name %s", str_int);
28     
29     return 0;
30 }
31 
32 -------------------------------------------------------------------------
33 Starting iteration 1.
34 Maximum number of concurrent connections per server: 6      [MsgId: MMSG-26989]
35 Starting action Action.
36 Action.c(15): Result:0
37 Action.c(19): Result:111
38 Action.c(24): New file name 56
39 Action.c(27): New file name 56
40 Ending action Action.
41 Ending iteration 1.