listing 1
#include <stdio.h>

int main()
{
  printf("|%10.5f|\n", 123.23);
  printf("|%-10.5f|\n", 123.23);
  printf("|%10.5s|\n", "Hello there");
  printf("|%-10.5s|\n", "Hello there");

  return 0;
}

listing 2
scanf("%d", &count);

listing 3
char address[80];
scanf("%s", address);

listing 4
scanf("%d%d", &r, &c);

listing 5
scanf("%d%*c%d", &x, &y);

listing 6
scanf("%20s", str);

listing 8
scanf("%c%c%c", &a, &b, &c);

listing 9
scanf("%st%s", &x, &y);

listing 10
scanf("%s ", name);

listing 11
%[XYZ]

listing 12
/* A simple scanset example. */
#include <stdio.h>

int main()
{
  char s1[80], s2[80];

  printf("Enter numbers, then some letters\n");
  scanf("%[0123456789]%s", s1, s2);
  printf("%s %s", s1, s2);

  return 0;
}

listing 13
%[A-Z]

listing 14
/* A scanset example using ranges. */
#include <stdio.h>

int main()
{
  char s1[80], s2[80];

  printf("Enter numbers, then some letters\n");
  scanf("%[0-9]%[a-zA-Z]", s1, s2);
  printf("%s %s", s1, s2);

  return 0;
}

listing 15
/* A scanset example using inverted ranges. */
#include <stdio.h>

int main()
{
  char s1[80], s2[80];

  printf("Enter non-numbers, then some non-letters\n");
  scanf("%[^0-9]%[^a-zA-Z]", s1, s2);
  printf("%s %s", s1, s2);

  return 0;
}

listing 16
fp = fopen("test", "w");

listing 17
if((fp = fopen("test", "w"))==NULL) {
  printf("Cannot open file.");
  exit(1);
}

listing 18
ch = fgetc(fp);

while(ch!=EOF) {
  ch = fgetc(fp);
}

listing 19
while(!feof(fp)) ch = fgetc(fp);

listing 20
/* This program will copy one file to another. */
#include <stdio.h>

int main(int argc, char *argv[])
{
  FILE *in, *out;
  char ch;

  if(argc!=3) {
    printf("You forgot to enter a filename\n");
    return 1;
  }

  if((in=fopen(argv[1], "rb")) == NULL) {
    printf("Cannot open source file.\n");
    return 1;
  }
  if((out=fopen(argv[2], "wb")) == NULL) {
    printf("Cannot open destination file.\n");
    return 1;
  }

  /* This code actually copies the file. */
  while(!feof(in)) {
     ch = fgetc(in);
     if(!feof(in)) fputc(ch, out);
  }

  fclose(in);
  fclose(out);

  return 0;
}

listing 21
/* Write a floating point number to a disk file. */
#include <stdio.h>

int main()
{
  FILE *fp;
  float f=12.23;

  if((fp=fopen("test","wb"))==NULL) {
    printf("Cannot open file.\n");
    return 1;
  }

  fwrite(&f, sizeof(float), 1, fp);

  fclose(fp);
  return 0;
}

listing 22
#include <stdio.h>

int main()
{
  register int i;
  FILE *fp;
  float balance[100];

  /* open for write */
  if((fp=fopen("balance","w"))==NULL) {
    printf("Cannot open file.\n");
    return 1;
  }

  for(i=0; i<100; i++) balance[i] = (float) i;

  /* This saves the entire balance array in one step. */
  fwrite(balance, sizeof balance, 1, fp);
  fclose(fp);

  /* zero array */
  for(i=0; i<100; i++) balance[i] = 0.0;

  /* open for read */
  if((fp=fopen("balance","r"))==NULL) {
    printf("Cannot open file.\n");
    return 1;
  }

  /* This reads the entire balance array in one step. */
  fread(balance, sizeof balance, 1, fp);

  /* display contents of array */
  for(i=0; i<100; i++) printf("%f ", balance[i]);

  fclose(fp);
  return 0;
}

listing 23
int func1()
{
  FILE *fp;

  if((fp=fopen("test", "rb")) == NULL) {
    printf("cannot open file\n");
    exit(1);
  }

  fseek(fp, 234L, SEEK_SET);
  return getc(fp);   /* read one character */
                     /* at 234th position */
  }
}