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#include <stdio.h>
/* The C Programming Language: 2nd Edition
*
* Exercise 1-22: Write a program to 'fold' long input lines into two or more
* shorter lines after the last non-blank character that occurs before the n-th
* column of input. Make sure your program does something intelligent with very
* long lines, and if there are no blanks or tabs before the specified column.
*
* Answer: So... Quite a hefty requirement. In a nutshell, our goal is to
* create sane hard-wrapping. This is a common function in text editors, and
* it's important to get it right or the results are wonky.
*
* TODO: get_line() is not fully correct. When it hits a \t, it counts it as
* one character and has no concept of display count. I'll fix this later on.
*/
// For tradition's sake, let's wrap at 80 columns
#define MAXLEN 80
char data[MAXLEN];
int i, j, k;
int get_line(char s[], int lim) {
/* Put as much as possible into a temp string, and count its length */
int c, i;
for (i = 0; i < lim && (c = getchar()) != EOF && c != '\n'; ++i) {
s[i] = c;
}
if (c == '\n') {
s[i] = c;
++i;
}
s[i] = '\0';
return i;
}
/* Find the first blank character, starting from the end of the string. Returns
* the position of the blank, or -1 if one wasn't found.
*/
int b_find_blank(char s[], int lim) {
// Start at the end of the string and go backwards.
for (i = lim; i >= 0; i--) {
// Simply replace the first blank with a newline.
if (s[i] == ' ' || s[i] == '\t') {
return i;
}
}
return -1;
}
int main() {
while (j = get_line(data, MAXLEN)) {
if (j == 80) {
// We know it's a long line now. Let's make sure we're breaking in
// the right place
k = b_find_blank(data, MAXLEN);
//printf("%d\n", k);
if (k > -1) {
data[k] = '\n';
data[MAXLEN] = '\0';
printf("%s", data);
continue;
} else {
data[MAXLEN] = '\0';
printf("%s\n", data);
continue;
}
}
printf("%s", data);
}
}
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