CS 1723, Frequency Program, an example with C structs, Tue Jan 06 1998, Page 1 of 2runner$ cat freq_struct.c/* Calculate fequencies of letters in an input file */#include <stdio.h>#include <ctype.h>struct table_tag { char letter; int count;};void bubble(struct table_tag table[]);void swap(struct table_tag *table1, struct table_tag *table2);void printfreq(struct table_tag table[], int tot);void main(void){ struct table_tag table[26]; int i; /* index for lc array */ int tot = 0; /* total number of alpha characters */ int ch; /* int so that EOF will work */ for (i = 0; i < 26; i++) { table[i].letter = (char) (i + ’a’); table[i].count = 0; } while ((ch = getchar()) != EOF) if (isalpha(ch = tolower(ch))) { tot++; table[ch - ’a’].count++; } bubble(table); printfreq(table, tot);}/* bubble: sort lc array into decreasing order. Carry alf along */void bubble(struct table_tag table[]){ int i, dum; for (dum = 0; dum < 25; dum++) for (i = 0; i < 25; i++) if (table[i].count < table[i+1].count) swap(&table[i], &table[i+1]);}/* swap: interchange two structs */void swap(struct table_tag *table1, struct table_tag *table2){ struct table_tag temp; temp = *table1; *table1 = *table2; *table2 = temp;}/* printfreq: print out the frequency table */void printfreq(struct table_tag table[], int tot){ int i; printf("Frequency of letters, out of total: %d\n\n", tot); printf(" Letter Frequency (%%)\n"); for (i = 0; i < 26; i++) printf("%6c %13.3f%%\n", table[i].letter, (double)table[i].count/tot*100.0);}runner$ freq_structAaAaAbbbBBbbbbbZzZzZZZzzZzzzzz (ctrl-D)Frequency of letters, out of total: 30 Letter Frequency (%) z 50.000% b 33.333% a 16.667%------------------------------------------------------runner% cat freq_typedef.c/* Calculate fequencies of letters in an input file *//* Variation using typedef */#include <stdio.h>#include <ctype.h>typedef struct { char letter; int count;} table_type;void bubble(table_type table[]);void swap(table_type *table1, table_type *table2);void printfreq(table_type table[], int tot);void main(void){ table_type table[26]; int i; /* index for lc array */ int tot = 0; /* total number of alpha characters */ int ch; /* int so that EOF will work */ for (i = 0; i < 26; i++) { table[i].letter = (char) (i + ’a’); table[i].count = 0; }CS 1723, Frequency Program, an example with C structs, Tue Jan 06 1998, Page 2 of 2 while ((ch = getchar()) != EOF) if (isalpha(ch = tolower(ch))) { tot++; table[ch - ’a’].count++; } bubble(table); printfreq(table, tot);}/* bubble: sort lc array into decreasing order. Carry alf along */void bubble(table_type table[]){ int i, dum; for (dum = 0; dum < 25; dum++) for (i = 0; i < 25; i++) if (table[i].count < table[i+1].count) swap(&table[i], &table[i+1]);}/* swap: interchange two structs */void swap(table_type *table1, table_type *table2){ table_type temp; temp = *table1; *table1 = *table2; *table2 = temp;}/* printfreq: print out the frequency table */void printfreq(table_type table[], int tot){ int i; printf("Frequency of letters, out of total: %d\n\n", tot); printf(" Letter Frequency (%%)\n"); for (i = 0; i < 26; i++) printf("%6c %13.3f%%\n", table[i].letter, (double)table[i].count/tot*100.0);}runner% cat freq_simp.c/* Calculate fequencies of letters in an input file *//* Variation using simple global arrays */#include <stdio.h>#include <ctype.h>char letter[26];int count[26];/* bubble: sort lc array into decreasing order. */void bubble(void){ int i, dum; for (dum = 0; dum < 25; dum++) for (i = 0; i < 25; i++) if (count[i] < count[i+1]) { int temp = count[i]; char tempc = letter[i]; count[i] = count[i+1]; letter[i] = letter[i+1]; count[i+1] = temp; letter[i+1] = tempc; }}/* printfreq: print out the frequency table */void printfreq(int tot){ int i; printf("Frequency of letters, out of total: %d\n\n", tot); printf(" Letter Frequency (%%)\n"); for (i = 0; i < 26; i++) printf("%6c %13.3f%%\n", letter[i], (double)count[i]/tot*100.0);}void main(void){ int i; /* index for lc array */ int tot = 0; /* total number of alpha characters */ int ch; /* int so that EOF will work */ for (i = 0; i < 26; i++) { letter[i] = (char) (i + ’a’); count[i] = 0; } while ((ch = getchar()) != EOF) if (isalpha(ch = tolower(ch))) { tot++; count[ch - ’a’]++; } bubble();