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#include <stdio.h>
#include <string.h>
/* The C Programming Language: 2nd Edition
*
* Exercise 7-8: Write a program to print a set of files, starting each new one
* on a new page, with a title and a running page count for each file.
*
* Notes: This could be done using functions written in exercise 7-2, but I
* decided to go with library functions when I could. A caveat to keep in mind
* on a real system is that the modern way to print some of the output is with
* snprintf, which doesn't exist in ANSI C. There are places where, to be safe,
* you should check bounds. Both line buffers are the same size here, however,
* so I didn't bother since I know they can hold each others' contents.
*
* If you were to do this correctly, it would be a lot like the `less` program.
*/
/* The dimensions of a "page". Using a classic size because reasons. */
#define PAGE_WIDTH 80
#define PAGE_HEIGHT 24
int lineno = 0;
int pageno = 0;
FILE *fp;
char buffer[PAGE_WIDTH];
char line[PAGE_WIDTH];
void page_break() {
while (lineno < (PAGE_HEIGHT - 1)) {
printf("\n");
lineno++;
}
}
int endswith_nl(char *s) {
int i;
for (i = 0; s[i] != '\0'; i++) {
}
if (i > 0 && s[i - 1] == '\n') {
return 1;
}
return 0;
}
void print_header(char *path) {
pageno++;
lineno++;
char *prefix = "FILE:";
sprintf(line, "%-*s %-*s", (int) strlen(prefix), prefix, (PAGE_WIDTH - ((int)strlen(prefix))), path);
printf("%s\n", line);
}
void print_footer(void) {
page_break();
sprintf(line, "Page %d\n", pageno);
printf("%*s", PAGE_WIDTH, line);
lineno = 0;
}
int main(int argc, char *argv[]) {
int i = 0;
char c;
while (argc > 1) {
i++;
argc--;
if ((fp = fopen(argv[i], "r"))) {
while ((c = fgetc(fp)) != EOF) {
ungetc(c, fp);
print_header(argv[i]);
while (fgets(buffer, PAGE_WIDTH, fp)) {
sprintf(line, "%s", buffer);
printf("%s", line);
if (!endswith_nl(line)) {
printf("\n");
}
lineno++;
if (lineno == (PAGE_HEIGHT - 1)) {
break;
}
}
print_footer();
}
fclose(fp);
pageno = 0;
} else {
printf("err: could not open file '%s' for reading.\n", argv[i]);
}
}
return 0;
}
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