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#include <stdio.h>
#define OUTPUT_WIDTH 72
#define LARGE_ARRSZ 500
#define SMALL_ARRSZ 5
struct bigram {
char trail, lead;
};
int
get_bigrams(char *text, struct bigram *bigrams, int max_bigrams)
{
char *trail=text, *lead=text+1;
int i=0;
while(*trail && *lead && (i<max_bigrams)) {
if (LARGE_ARRSZ<i) {
return -1;
}
bigrams[i].trail = *trail++;
bigrams[i].lead = *lead++;
i++;
}
return i;
}
void
print_bigrams(struct bigram *bigrams, int num_bigrams, int line_width)
{
int i, retval=0;
for(i = 0; i < num_bigrams; i += 1) {
retval += (printf("%c%c/", bigrams->trail, bigrams->lead));
if (retval > line_width) {
printf("\n");
retval=0;
}
*bigrams++;
}
printf("\n");
}
void
test1(char *my_text)
{
struct bigram largeArr[LARGE_ARRSZ];
int num_bigrams;
if ((num_bigrams = get_bigrams(my_text, largeArr, LARGE_ARRSZ))<LARGE_ARRSZ) {
printf("%d bigrams:\n", num_bigrams);
print_bigrams(largeArr, num_bigrams, OUTPUT_WIDTH);
}
}
void
test2(char *my_text)
{
struct bigram smallArr[SMALL_ARRSZ+1];
int num_bigrams;
smallArr[SMALL_ARRSZ].lead = '@'; /* sentinel for overwrites */
if ((num_bigrams = get_bigrams(my_text, smallArr, SMALL_ARRSZ))<SMALL_ARRSZ) {
printf("wrong bigram count!\n");
}
if (smallArr[SMALL_ARRSZ].lead!='@') {
printf("buffer overflow :-(\n");
}
}
int
do_something(char *text, struct bigram *bigrams, int max)
{
char *trail=text, *lead=text+1;
int i=0;
while(*trail && *lead && (i < max)) {
bigrams[i].trail = *trail++;
bigrams[i].lead = *lead++;
i++;
}
for(unsigned int j = 0; j < max; j += 1) {
printf("%c%c/\n", bigrams[j].trail, bigrams[j].lead);
}
printf("%d\n", i);
return i;
}
int main(void)
{
struct bigram b = {'a', 'b'};
struct bigram b1 = {'b', 'c'};
struct bigram bigrams[3];
*bigrams = b;
*(bigrams+1) = b1;
for(unsigned int i = 0; i < 2; i += 1) {
printf("%c%c\n", bigrams[i].trail, bigrams[i].lead);
}
struct bigram bigrams1[3];
char *text = "abcd";
int max=3;
do_something(text, bigrams1, max);
char *my_text = "Ein Gespenst geht um in Europa";
test1(my_text);
test2(my_text);
return 0;
}
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