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#include <stdio.h>
#include <string.h>
#define ESCAPE 0
#define UNESCAPE 1
#define MAXLEN 1000
/* convert new line and tab chars to visible chars */
void escape(char s[], char t[]);
/* converts escapes sequences to chars */
void unescape(char s[], char t[]);
int main(int argc, char *argv[]) {
int c, i, cmd;
char s[MAXLEN], t[MAXLEN];
if (!strcmp(argv[1], "e"))
cmd = ESCAPE;
else if (!strcmp(argv[1], "u"))
cmd = UNESCAPE;
else
return 1;
printf("Enter string to %s and press Ctrl+D\n",
cmd == ESCAPE ? "escape" : "unescape");
for (i = 0; i < MAXLEN - 1 && (c = getchar()) != EOF; i++)
t[i] = c;
t[i] = 0;
if (cmd == ESCAPE) {
escape(s, t);
printf("Escaped output:\n");
printf("%s\n", s);
} else if (cmd == UNESCAPE) {
unescape(s, t);
printf("Unescaped output:\n");
printf("%s\n", s);
} else {
return 1;
}
return 0;
}
void escape(char s[], char t[]) {
int c, i, j;
for (i = 0, j = 0; (c = t[i]) != 0; i++) {
switch (c) {
case '\n': {
s[j++] = '\\';
s[j++] = 'n';
break;
}
case '\t': {
s[j++] = '\\';
s[j++] = 't';
break;
}
default:
s[j++] = c;
}
s[j] = 0;
}
}
void unescape(char s[], char t[]) {
int c, i, j;
for (i = 0, j = 0; (c = t[i]) != 0; i++) {
if (j > 0 && s[j - 1] == '\\') {
switch (c) {
case 'n':
s[j - 1] = '\n';
break;
case 't':
s[j - 1] = '\t';
break;
default:
s[j++] = c;
}
} else {
s[j++] = c;
}
}
s[j] = 0;
}
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