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关闭窗口 功 能: 设置可见图形页号
用 法: void far setvisualpage(int pagenum);
程序例:
#include
#include
#include
#include
int main(void)
{
/* select a driver and mode that supports */
/* multiple pages. */
int gdriver = EGA, gmode = EGAHI, errorcode;
int x, y, ht;
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
x = getmaxx() / 2;
y = getmaxy() / 2;
ht = textheight("W");
/* select the off screen page for drawing */
setactivepage(1);
/* draw a line on page #1 */
line(0, 0, getmaxx(), getmaxy());
/* output a message on page #1 */
settextjustify(CENTER_TEXT, CENTER_TEXT);
outtextxy(x, y, "This is page #1:");
outtextxy(x, y+ht, "Press any key to halt:");
/* select drawing to page #0 */
setactivepage(0);
/* output a message on page #0 */
outtextxy(x, y, "This is page #0.");
outtextxy(x, y+ht, "Press any key to view page #1:");
getch();
/* select page #1 as the visible page */
setvisualpage(1);
/* clean up */
getch();
closegraph();
return 0;
}
函数名: setwritemode
功 能: 设置图形方式下画线的输出模式
用 法: void far setwritemode(int mode);
程序例:
#include
#include
#include
#include
int main()
{
/* request auto detection */
int gdriver = DETECT, gmode, errorcode;
int xmax, ymax;
/* initialize graphics and local variables */
initgraph(&gdriver, &gmode, "");
/* read result of initialization */
errorcode = graphresult();
if (errorcode != grOk) /* an error occurred */
{
printf("Graphics error: %s\n", grapherrormsg(errorcode));
printf("Press any key to halt:");
getch();
exit(1); /* terminate with an error code */
}
xmax = getmaxx();
ymax = getmaxy();
/* select XOR drawing mode */
setwritemode(XOR_PUT);
/* draw a line */
line(0, 0, xmax, ymax);
getch();
/* erase the line by drawing over it */
line(0, 0, xmax, ymax);
getch();
/* select overwrite drawing mode */
setwritemode(COPY_PUT);
/* draw a line */
line(0, 0, xmax, ymax);
/* clean up */
getch();
closegraph();
return 0;
}
函数名: signal
功 能: 设置某一信号的对应动作
用 法: int signal(int sig, sigfun fname);
程序例:
/* This example installs a signal handler routine for SIGFPE,
catches an integer overflow condition, makes an adjustment
to AX register, and returns. This example program MAY cause
your computer to crash, and will produce runtime errors
depending on which memory model is used.
*/
#pragma inline
#include
#include
void Catcher(int sig, int type, int *reglist)
{
printf("Caught it!\n");
*(reglist + 8) = 3; /* make return AX = 3 */
}
int main(void)
{
signal(SIGFPE, Catcher);
asm mov ax,07FFFH /* AX = 32767 */
asm inc ax /* cause overflow */
asm into /* activate handler */
/* The handler set AX to 3 on return. If that hadn’t happened,
there would have been another exception when the next ’into’
was executed after the ’dec’ instruction. */
asm dec ax /* no overflow now */
asm into /* doesn’t activate */
return 0;
}
函数名: sin
功 能: 正弦函数
用 法: double sin(double x);
程序例:
#include
#include
int main(void)
{
double result, x = 0.5;
result = sin(x);
printf("The sin() of %lf is %lf\n", x, result);
return 0;
}
函数名: sinh
功 能: 双曲正弦函数
用 法: double sinh(double x);
程序例:
#include
#include
int main(void)
{
double result, x = 0.5;
result = sinh(x);
printf("The hyperbolic sin() of %lf is %lf\n", x, result);
return 0;
}
函数名: sleep
功 能: 执行挂起一段时间
用 法: unsigned sleep(unsigned seconds);
程序例:
#include
#include
int main(void)
{
int i;
for (i=1; i<5; i++)
{
printf("Sleeping for %d seconds\n", i);
sleep(i);
}
return 0;
}
函数名: sopen
功 能: 打开一共享文件
用 法: int sopen(char *pathname, int access, int shflag, int permiss);
程序例:
#include
#include
#include
#include
#include
#include
int main(void)
{
int handle;
int status;
handle = sopen("c:\\autoexec.bat", O_RDONLY, SH_DENYNO, S_IREAD);
if (!handle)
{
printf("sopen failed\n");
exit(1);
}
status = access("c:\\autoexec.bat", 6);
if (status == 0)
printf("read/write access allowed\n");
else
printf("read/write access not allowed\n");
close(handle);
return 0;
}
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
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
#include
#include
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
#include
#include
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
#include
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
#include
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
#include
#include
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
#include
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
{
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
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
#include
#include
#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
#include
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
#include
#include
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
#include
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
#include
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
#include
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
#include
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
#include
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
#include
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
#include
#include
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;
}
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
#include
#include
int main(void)
{
char *dup_str, *string = "abcde";
dup_str = strdup(string);
printf("%s\n", 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
#include
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;
}
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
#include
int main(void)
{
char *buffer;
buffer = strerror(errno);
printf("Error: %s\n", 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
#include
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: strncmp
功 能: 串比较
用 法: int strncmp(char *str1, char *str2, int maxlen);
程序例:
#include
#include
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);
}
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
#include
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;
}
函数名: strncpy
功 能: 串拷贝
用 法: char *strncpy(char *destin, char *source, int maxlen);
程序例:
#include
#include
int main(void)
{
char string[10];
char *str1 = "abcdefghi";
strncpy(string, str1, 3);
string[3] = ’\0’;
printf("%s\n", 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
#include
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;
}
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
#include
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;
}
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
#include
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;
}
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
#include
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;
}
函数名: strrev
功 能: 串倒转
用 法: char *strrev(char *str);
程序例:
#include
#include
int main(void)
{
char *forward = "string";
printf("Before strrev(): %s\n", forward);
strrev(forward);
printf("After strrev(): %s\n", 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
#include
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;
}
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
#include
#include
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;
}
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
#include
int main(void)
{
char *str1 = "Borland International", *str2 = "nation", *ptr;
ptr = strstr(str1, str2);
printf("The substring is: %s\n", 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
#include
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;
}
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
#include
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;
}
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
#include
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;
}
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
#include
int main(void)
{
char *string = "abcdefghijklmnopqrstuvwxyz", *ptr;
/* converts string to upper case characters */
ptr = strupr(string);
printf("%s\n", 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
#include
#include
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;
}
函数名: system
功 能: 发出一个DOS命令
用 法: int system(char *command);
程序例:
#include
#include
int main(void)
{
printf("About to spawn command.com and run a DOS command\n");
system("dir");
return 0;
}
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