c语言库函数(s类字母) - 3.txt

C语言库函数合集

函数名: sound  
功  能: 以指定频率打开PC扬声器  
用  法: void sound(unsigned frequency);  
程序例:  

/* Emits a 7-Hz tone for 10 seconds.  
   Your PC may not be able to emit a 7-Hz tone. */  
#include <dos.h>  

int main(void)  
{  
   sound(7);  
   delay(10000);  
   nosound();  
   return 0;  
}  
   
   
   

函数名: spawnl  
功  能: 创建并运行子程序  
用  法: int spawnl(int mode, char *pathname, char *arg0,  
     arg1, ... argn, NULL);  
程序例:  

#include <process.h>  
#include <stdio.h>  
#include <conio.h>  

int main(void)  
{  
   int result;  

   clrscr();  
   result = spawnl(P_WAIT, "tcc.exe", NULL);  
   if (result == -1)  
   {  
      perror("Error from spawnl");  
      exit(1);  
   }  
   return 0;  
}  
   
   

函数名: spawnle  
功  能: 创建并运行子程序  
用  法: int spawnle(int mode, char *pathname, char *arg0,  
      arg1,..., argn, NULL);  
程序例:  

/* spawnle() example */  

#include <process.h>  
#include <stdio.h>  
#include <conio.h>  

int main(void)  
{  
   int result;  

   clrscr();  
   result = spawnle(P_WAIT, "tcc.exe", NULL, NULL);  
   if (result == -1)  
   {  
      perror("Error from spawnle");  
      exit(1);  
   }  
   return 0;  
}  
   
   
   

函数名: sprintf  
功  能: 送格式化输出到字符串中  
用  法: int sprintf(char *string, char *farmat [,argument,...]);  
程序例:  

#include <stdio.h>  
#include <math.h>  

int main(void)  
{  
   char buffer[80];  

   sprintf(buffer, "An approximation of Pi is %f\n", M_PI);  
   puts(buffer);  
   return 0;  
}  
   
   

函数名: sqrt  
功  能: 计算平方根  
用  法: double sqrt(double x);  
程序例:  

#include <math.h>  
 #include <stdio.h>  

 int main(void)  
 {  
    double x = 4.0, result;  

    result = sqrt(x);  
    printf("The square root of %lf is %lf\n", x, result);  
    return 0;  
}  
   

函数名: srand  
功  能: 初始化随机数发生器  
用  法: void srand(unsigned seed);  
程序例:  

#include <stdlib.h>  
#include <stdio.h>  
#include <time.h>  

int main(void)  
{  
   int i;  
   time_t t;  

   srand((unsigned) time(&t));  
   printf("Ten random numbers from 0 to 99\n\n");  
   for(i=0; i<10; i++)  
       printf("%d\n", rand() % 100);  
   return 0;  
}  
   
   

函数名: sscanf  
功  能: 执行从字符串中的格式化输入  
用  法: int sscanf(char *string, char *format[,argument,...]);  
程序例:  

#include <stdio.h>  
#include <conio.h>  

int main(void)  
{  
   char label[20];  
   char name[20];  
   int entries = 0;  
   int loop, age;  
   double salary;  

   struct Entry_struct  
   {  
      char  name[20];  
      int   age;  
      float salary;  
   } entry[20];  

/* Input a label as a string of characters restricting to 20 characters */  
   printf("\n\nPlease enter a label for the chart: ");  
   scanf("%20s", label);  
   fflush(stdin);  /* flush the input stream in case of bad input */  

/* Input number of entries as an integer */  
   printf("How many entries will there be? (less than 20) ");  
   scanf("%d", &entries);  
   fflush(stdin);   /* flush the input stream in case of bad input */  

/* input a name restricting input to only letters upper or lower case */  
   for (loop=0;loop<entries;++loop)  
   {  
      printf("Entry %d\n", loop);  
      printf("  Name   : ");  
      scanf("%[A-Za-z]", entry[loop].name);  
      fflush(stdin);  /* flush the input stream in case of bad input */  

/* input an age as an integer */  
      printf("  Age    : ");  
      scanf("%d", &entry[loop].age);  
      fflush(stdin);  /* flush the input stream in case of bad input */  

/* input a salary as a float */  
      printf("  Salary : ");  
      scanf("%f", &entry[loop].salary);  
      fflush(stdin); /* flush the input stream in case of bad input */  
   }  

/* Input a name, age and salary as a string, integer, and double */  
   printf("\nPlease enter your name, age and salary\n");  
   scanf("%20s %d %lf", name, &age, &salary);  
   

/* Print out the data that was input */  
   printf("\n\nTable %s\n",label);  
   printf("Compiled by %s  age %d  $%15.2lf\n", name, age, salary);  
   printf("-----------------------------------------------------\n");  
   for (loop=0;loop<entries;++loop)  
      printf("%4d | %-20s | %5d | %15.2lf\n",  
         loop + 1,  
  entry[loop].name,  
  entry[loop].age,  
  entry[loop].salary);  
   printf("-----------------------------------------------------\n");  
   return 0;  
}  
   
   

函数名: stat  
功  能: 读取打开文件信息  
用  法: int stat(char *pathname, struct stat *buff);  
程序例:  

#include <sys\stat.h>  
#include <stdio.h>  
#include <time.h>  

#define FILENAME "TEST.$$$"  

int main(void)  
{  
   struct stat statbuf;  
   FILE *stream;  

   /* open a file for update */  
   if ((stream = fopen(FILENAME, "w+")) == NULL)  
   {  
      fprintf(stderr, "Cannot open output file.\n");  
      return(1);  
   }  

   /* get information about the file */  
   stat(FILENAME, &statbuf);  

   fclose(stream);  

   /* display the information returned */  
   if (statbuf.st_mode & S_IFCHR)  
      printf("Handle refers to a device.\n");  
   if (statbuf.st_mode & S_IFREG)  
      printf("Handle refers to an ordinary file.\n");  
   if (statbuf.st_mode & S_IREAD)  
      printf("User has read permission on file.\n");  
   if (statbuf.st_mode & S_IWRITE)  
      printf("User has write permission on file.\n");  

   printf("Drive letter of file: %c\n", 'A'+statbuf.st_dev);  
   printf("Size of file in bytes: %ld\n", statbuf.st_size);  
   printf("Time file last opened: %s\n", ctime(&statbuf.st_ctime));  
   return 0;  
}  
   
   
   

函数名: _status87  
功  能: 取浮点状态  
用  法: unsigned int _status87(void);  
程序例:  

#include <stdio.h>  
#include <float.h>  

int main(void)  
{  
   float x;  
   double y = 1.5e-100;  

   printf("Status 87 before error: %x\n", _status87());  

   x = y;  /* <-- force an error to occur */  
   y = x;  

   printf("Status 87 after error : %x\n", _status87());  
   return 0;  
}  
   
   

函数名: stime  
功  能: 设置时间  
用  法: int stime(long *tp);  
程序例:  

#include <stdio.h>  
#include <time.h>  
#include <dos.h>  

int main(void)  
{  
   time_t t;  
   struct tm *area;  

   t = time(NULL);  
   area = localtime(&t);  
   printf("Number of seconds since 1/1/1970 is: %ld\n", t);  
   printf("Local time is: %s", asctime(area));  

   t++;  
   area = localtime(&t);  
   printf("Add a second:  %s", asctime(area));  

   t += 60;  
   area = localtime(&t);  
   printf("Add a minute:  %s", asctime(area));  

   t += 3600;  
   area = localtime(&t);  
   printf("Add an hour:   %s", asctime(area));  

   t += 86400L;  
   area = localtime(&t);  
   printf("Add a day:     %s", asctime(area));  

   t += 2592000L;  
   area = localtime(&t);  
   printf("Add a month:   %s", asctime(area));  

   t += 31536000L;  
   area = localtime(&t);  
   printf("Add a year:    %s", asctime(area));  
   return 0;  
}  
   
   
   

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);  
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;  
 }