chap19.lst

Borland C++ Builder The Complete Reference 例程源代码

listing 1
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  char num[80]; 
 
  gets(num); 
  printf("Absolute value is %d.\n", abs(atoi(num))); 
 
  return 0; 
}

listing 2
ch = read_port(); 
assert(!(ch & 128)); /* check bit 7 */ 

listing 3
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  char num1[80], num2[80]; 
 
  printf("Enter first number: "); 
  gets(num1); 
  printf("Enter second number: "); 
  gets(num2); 
  printf("The sum is: %f", atof(num1)+atof(num2)); 
 
  return 0; 
}

listing 4
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  char num1[80], num2[80]; 
 
  printf("Enter first number: "); 
  gets(num1); 
  printf("Enter second number: "); 
  gets(num2); 
  printf("The sum is: %d", atoi(num1)+atoi(num2)); 
 
  return 0; 
}

listing 5
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  char num1[80], num2[80]; 
 
  printf("Enter first number: "); 
  gets(num1); 
  printf("Enter second number: "); 
  gets(num2); 
  printf("The sum is: %ld", atol(num1)+atol(num2)); 
 
  return 0; 
}

listing 6
#include <stdio.h> 
#include <stdlib.h> 
#include <ctype.h> 
 
char *alpha="abcdefghijklmnopqrstuvwxyz"; 
int comp(const void *, const void *); 
 
int main(void) 
{ 
  char ch; 
  char *p; 
 
  do { 
    printf("Enter a character: "); 
    scanf("%c%*c", &ch); 
    ch = tolower(ch); 
    p = (char *) bsearch(&ch, alpha, 26, 1, comp); 
    if(p) printf("is in alphabet\n"); 
    else printf("is not in alphabet\n"); 
  } while(p); 
 
  return 0; 
} 
 
/* Compare two characters. */ 
int comp(const void *ch, const void *s) 
{ 
  return *(char *)ch - *(char *)s; 
}

listing 7
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  div_t n; 
 
  n = div(10,3); 
  printf("Quotient and remainder: %d %d\n", n.quot, n.rem); 
 
  return 0; 
}

listing 8
int decpnt, sign; 
char *out; 
 
out = ecvt(10.12, 5, &decpnt, &sign);

listing 9
int decpnt, sign; 
char *out; 
 
out = fcvt(10.12, 5, &decpnt, &sign);

listing 10
/* compute and print payroll checks */ 
system("payroll"); 
_fpreset();

listing 11
char buf[80]; 
gcvt(10.12, 5, buf);

listing 12
p = getenv("PATH");

listing 13
#include <conio.h> 
#include <string.h> 
 
void pswd (char *pw) 
{ 
  char *input; 
 
  do { 
    input = getpass("Enter your password:"); 
  }while (strcmp("starbar", input)); 
 
  printf("You're in!"); 
}

listing 14
printf("This process ID of this program is %d\n", getpid());

listing 15
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  char p[17]; 
 
  itoa(1423, p, 16); 
  printf(p); 
 
  return 0; 
}

listing 16
#include <stdio.h> 
#include <stdlib.h> 
 
long int get_labs() 
{ 
  char num[80]; 
 
  gets(num); 
 
  return labs(atol(num)); 
}

listing 17
long quot;  /* the quotient */ 
long rem;   /* the remainder */

listing 18
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  ldiv_t n; 
 
  n = ldiv(100000L,3L); 
  printf("Quotient and remainder: %ld %ld.\n", n.quot, n.rem); 
 
  return 0; 
}

listing 19
#include <stdlib.h> 
#include <ctype.h> 
#include <stdio.h> 
 
char *alpha="abcdefghijklmnopqrstuvwxyz"; 
 
int comp(const void *, const void *); 
 
int main(void) 
{ 
  char ch; 
  char *p; 
  size_t num=26; 
 
  do { 
    printf("Enter a character: "); 
    scanf("%c%*c", &ch); 
    ch = tolower(ch);| 
 
    p = (char *) lfind(&ch, alpha, &num, 1, comp); 
 
    if(p) printf("is in alphabet\n"); 
    else printf("is not in alphabet\n"); 
  } while(p); 
 
  return 0; 
} 
 
/* Compare two characters. */ 
int comp(const void *ch, const void *s) 
{ 
  return *(char *)ch - *(char *)s; 
}

listing 20
#include <stdio.h> 
#include <setjmp.h> 
#include <stdlib.h> 
 
jmp_buf ebuf; 
void f2(void); 
 
int main(void) 
{ 
  int i; 
 
  printf("1 "); 
  i = setjmp(ebuf); 
  if ( i !=0 ) { 
     printf("%d",i); 
     exit(1); 
  } 
  f2(); 
 
  return 0; 
} 
 
void f2(void) 
{ 
  printf("2 "); 
  longjmp(ebuf, 3); 
}

listing 21
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  char p[34]; 
 
  ltoa(1423, p, 16); 
  printf(p); 
 
  return 0; 
}

listing 22
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  unsigned long l = 1; 
  printf("1 rotated left 2 bits = %ld\n", _lrotl(l,2)); 
  l=16; 
  printf("16 rotated right 2 bits = %ld\n", _lrotr(l,2)); 
 
  return 0; 
}

listing 23
#include <stdlib.h> 
#include <stdio.h> 
 
int main (void) 
{ 
  printf("max of 10, 20 is %d\n", max (10, 20)); 
  printf("min of 10, 20 is %d\n", min (10, 20)); 
 
  return 0; 
}

listing 24
printf("%d", mblen(mb, 2));

listing 25
mbstowcs(wstr, mb, 4);

listing 26
mbtowc(wstr, mbstr, 2);

listing 27
#include <stdio.h> 
#include <stdlib.h> 
 
int num[10] = { 
  1,3,6,5,8,7,9,6,2,0 
}; 
 
int comp(const int *, const int *); 
 
int main(void) 
{ 
  int i; 
 
  printf("Original array: "); 
  for(i=0; i<10; i++) printf("%d ",num[i]); 
  printf("\n"); 
 
  qsort(num, 10, sizeof(int), 
        (int(*)(const void *, const void *)) comp); 
 
  printf("Sorted array: "); 
  for(i=0; i<10; i++) printf("%d ", num[i]); 
 
  return 0; 
} 
 
/* compare the integers */ 
int comp(const int *i, const int *j) 
{  
  return *i - *j; 
}

listing 28
#include <signal.h> 
#include <stdio.h> 
#include <stdlib.h> 
 
void myhandler(int); 
 
int main(void) 
{ 
  signal(SIGTERM, myhandler); 
  raise(SIGTERM); 
  printf("This line will not be executed.\n"); 
 
  return 0; 
} 
 
void myhandler(int notused) 
{ 
  printf("Program terminated.\n"); 
  exit(1); 
}

listing 29
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  int i; 
 
  for(i=0; i<10; i++) 
    printf("%d ", rand()); 
 
  return 0; 
}

listing 30
#include <time.h> 
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  int i; 
 
  randomize(); 
  for(i=0; i<10; i++) printf("%d ", random(25)); 
 
  return 0; 
}

listing 31
#include <stdio.h> 
#include <stdlib.h> 
 
int main(void) 
{ 
  unsigned val = 64; 
 
  printf("Rotated left 2 bits = %d\n", _rotl(val,2)); 
  printf("Rotated right 2 bits = %d\n", _rotr(val,2)); 
 
  return 0; 
}

listing 32
_setcursortype(_SOLIDCURSOR);

listing 33
#include <stdio.h> 
#include <setjmp.h> 
#include <stdlib.h> 
 
jmp_buf ebuf; 
void f2(void); 
 
int main(void) 
{ 
  int i; 
 
  printf("1 "); 
  i = setjmp(ebuf); 
  if(i != 0) { 
    printf("%d",i); 
    exit(1); 
  } 
  f2(); 
 
  return 0; 
} 
 
void f2(void) 
{ 
  printf("2 "); 
  longjmp(ebuf, 3); 
}

listing 34
#include <stdlib.h> 
#include <stdio.h> 
 
int main(int argc, char *argv[]) 
{ 
  char fpath[64]; 
 
  if(argc!=3) { 
    printf("Usage: FINDFILE <fname> <ename>"); 
    return 1; 
  } 
 
  _searchenv(argv[1], argv[2], fpath); 
 
  /* fpath will contain path if file is found */ 
  if(*fpath) printf("Path: %s", fpath); 
 
  return 0; 
}

listing 35
signal(SIGINT, myint);

listing 36
#include <stdio.h> 
#include <stdlib.h> 
#include <time.h> 
 
/* Seed rand with the system time 
   and display the first 10 numbers. 
*/ 
int main(void) 
{ 
  int i, stime; 
  long  ltime; 
 
  /* get the current calendar time */ 
 
  ltime = time(NULL); 
  stime = (unsigned int) ltime/2; 
  srand(stime); 
  for(i=0; i<10; i++) printf("%d ", rand()); 
 
  return 0; 
}

listing 37
#include <stdio.h> 
#include <stdlib.h> 
#include <ctype.h> 
 
int main(void) 
{ 
  char *end, *start="100.00 pliers 200.00 hammers"; 
 
  end = start; 
  while(*start) { 
    printf("%f, ",strtod(start, &end)); 
    printf("Remainder: %s\n", end); 
    start = end; 
    /* move past the non-digits */ 
    while(!isdigit(*start) && *start) start++; 
  } 
 
  return 0; 
}

listing 38
100.000000, Remainder: pliers 200.00 hammers 
200.000000, Remainder: hammers

listing 39
#include <stdio.h> 
#include <stdlib.h> 
 
long int read_long() 
{ 
  char start[80], *end; 
 
  printf("Enter a number: "); 
  gets(start); 
  return strtol(start, &end, 10); 
}

listing 40
char dest[3]; 
 
swab("Hi", dest, 2); 
printf(dest);

listing 41
#include <stdlib.h> 
 
int main(void) 
{ 
  system("dir"); 
 
  return 0; 
}

listing 42
int ch; 
ch = getche(): 
ch = toascii(ch);

listing 43
umask(S_IREAD);

listing 44
#include <utime.h> 
#include <stdio.h> 
 
int main(int argc, char *argv[]) 
{ 
  if(argc!=2) { 
    printf("Usage: SETTIME <fname>"); 
    return 1; 
  } 
 
  /* set to current system time */ 
  utime(argv[1], NULL); 
 
  return 0; 
}

listing 45
/* Variable length argument example - sum a series.*/ 
 
#include <stdio.h> 
#include <stdarg.h> 
 
double sum_series(int, ...); 
 
int main(void) 
{ 
  double d; 
 
  d = sum_series(5, 0.5, 0.25, 0.125, 0.0625, 0.03125); 
  printf("Sum of series is %f\n",d); 
 
  return 0; 
} 
 
double sum_series(int num, ...) 
{ 
  double sum = 0.0, t; 
  va_list argptr; 
 
  /* initialize argptr */ 
  va_start(argptr, num); 
 
  /* sum the series */ 
  for(; num; num--) { 
   t = va_arg(argptr,double); 
   sum += t; 
  } 
 
  /* do orderly shutdown */ 
  va_end(argptr); 
  return sum; 
}