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19
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fonenum.c
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C/C++ Source or Header
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1990-08-05
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4KB
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115 lines
/* FONENUM.C searches a file for a phone number using only */
/* the (supplied) lastname, and also allows additions of */
/* names to the file when "enter" is the lastname supplied */
/* This is deliberately written with function declarations */
/* preceding function use, for strict ANSI argument checks */
/* and no need of a header file. Things are defined in */
/* one place only. Globals are carefully minimized. */
/* My formatting philosophy is to keep all of a function */
/* on a single page and to have that deal with one thought */
#include <stdio.h>
#include <string.h>
#define MAXLASTNM 30
#define MAXFIRSTNM 15
#define MAXFONENUM 12
#define DATABASE "input"
struct record {
char lastname[MAXLASTNM + 1];
char firstname[MAXFIRSTNM + 1];
char phonenum[MAXFONENUM + 1];
};
/* ------------------------------------ */
/* emit program calling syntax verbiage */
void
help(void) {
puts("Usage: FONENUM <name> ");
puts(" Where <name> is the lastname of the person.");
puts(" In order to add names to the file, enter the");
puts(" word 'Enter' as the name of the person.");
} /* help */
/* ----------------------------------------- */
/* prompt and get input string, limit length */
void
promptget(char *prompt, char *answer, int maxlgh) {
int i;
printf(prompt); fflush(stdin); /* reverse order ?? */
fgets(answer, maxlgh, stdin);
/* There MUST be clearer and better code for the rest */
if (answer[strlen(answer)-1] == '\n') /* remove any trailing \n */
answer[strlen(answer)-1] = 0;
for (i = strlen(answer); i <= maxlgh; i++) { /* clean string */
answer[i] = 0;
}
} /* promptget */
/* ---------------------------------------------- */
/* get record data from stdin and add to database */
void
addrecords(FILE *fptr) {
struct record currentitem;
promptget("Enter last name: ", currentitem.lastname, MAXLASTNM);
promptget("Enter first name: ", currentitem.firstname, MAXFIRSTNM);
promptget("Phone number (XXX-XXX-XXXX): ", currentitem.phonenum,
MAXFONENUM);
if (0 == fwrite(¤titem, sizeof(currentitem), 1, fptr)) {
puts("Write failure");
}
} /* addrecords */
/* ---------------------------------------------- */
/* display all database records matching searchee */
void
displaymatches(FILE *fptr, char *searchee) {
struct record currentitem;
int names, count;
names = count = 0;
while (0 != fread(¤titem, sizeof(currentitem), 1, fptr)) {
if (0 == strcmpi(currentitem.lastname, searchee)) {
printf("\n%s %s: %s", currentitem.firstname,
currentitem.lastname,
currentitem.phonenum);
names++;
}
count++;
}
} /* displaymatches */
/* ---------------------------------- */
/* Main body and overall flow control */
void
main(int argc, char *argv[]) {
FILE *fptr;
if (argc != 2) help(); /* extra or no params mean misentry */
else if (0 == strcmpi("enter", argv[1])) { /* loading */
if (NULL == (fptr = fopen(DATABASE, "ab"))) {
puts("Cannot open file for storing data.");
}
else { /* successful open */
addrecords(fptr);
fclose(fptr);
}
}
else if (NULL == (fptr = fopen(DATABASE, "rb"))) { /* searching */
puts("Cannot open file for reading data.");
}
else { /* successful open */
displaymatches(fptr, argv[1]);
fclose(fptr);
}
} /* main */