1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
|
/*
* Purpose: To generate a calender.
* Author: M J Leslie
* Date: 19-Mar-94
*/
#include <stdio.h>
#define TRUE 1
#define FALSE 0
#define DAYS_IN_A_WEEK 7
#define MAX_COLS 6
#define BASE_YEAR 1990 /* Year from which all
calculations are done. */
/* Function declatations */
int calender_month(const int month, const int year);
int start_day(const int month, const int year);
int leap(int);
/* Global variables. */
int days_in_month[]={0,31,28,31,30,31,30,31,31,30,31,30,31};
main(int argc, char *argv[])
{
int i; /* General purpose var */
int year; /* year to start display */
int num_of_months; /* Number of months */
int start_month; /* Start month */
int month; /* Current month */
char *prog=argv[0]; /* Program name */
/* Check we have the
program name and 3 parms */
if ( argc != 4)
{
puts("\tProgram syntax:");
printf("\t\t%s start_month start_year num_of_months",prog );
exit(1);
}
/* Dont bother checking if the
parms are integers!! */
/* Put command line parms into
meaningfull variable names */
start_month = atoi(argv[1]);
year = atoi(argv[2]);
num_of_months = atoi(argv[3]);
/* AND OFF WE GO... */
month = start_month;
for (i=start_month; i < start_month + num_of_months ; i++)
{
calender_month(month, year); /* O/P one month. */
if ( month++ >= 12) /* Q. End of year? */
{ /* Yes. */
month = 1;
year++;
}
}
}
/************************************************************************/
/* Calender_month */
/* Display one calender month. */
/************************************************************************/
calender_month(const int month, const int year)
{
int i,j,count; /* General Purpose variables. */
/* dont forget - arrays start
at zero */
char *days[]=
{
" ",
"Mon",
"Tue",
"Wed",
"Thr",
"Fri",
"Sat",
"Sun"
};
char *months[]=
{
" ",
"January",
"Febuary",
"March",
"April",
"May",
"June",
"July",
"August",
"September",
"October",
"November",
"December"
};
int month_map[8][MAX_COLS+1]={0}; /* init array with zeros */
j=start_day(month, year); /* Get the day the month starts */
/* Build the calender values */
i=1;count=0;
while ( days_in_month[month] > count)
{
month_map[j++][i]=++count; /* Build the table. */
/* Start a new week. */
if ( j > DAYS_IN_A_WEEK)
{
j=1;
i++;
}
}
/* O/P Title bar. */
printf("\n\t\t%s %d\n\n",months[month], year);
/* O/P the calender */
for (j=1; j<=DAYS_IN_A_WEEK; j++)
{
printf("\t%s ",days[j]); /* Day names */
for (i=1; i<=MAX_COLS; i++)
{
if ( month_map[j][i] == 0 ) /* dates */
{printf (" ");}
else
{printf ("%2d ", month_map[j][i]);}
}
puts (""); /* puts supplies a Newline */
}
}
/************************************************************************/
/* Start_day */
/* Work out which day the month starts on. */
/************************************************************************/
int start_day(const int month, const int year)
{
int day=1; /* 1/1/1990 was a Monday. */
int i,j; /* GP work variable. */
/* Count days in the year. */
i = BASE_YEAR;
while ( i < year )
{
leap(i); /* Check for leap years */
for (j=1; j<=12; j++) day = day + days_in_month[j];
i++;
}
/* Count upto the month required */
i=1;
leap(year); /* Check for leap years */
while ( i < month )
{
day = day + days_in_month[i++];
}
/* Get modulo and return it as
the start day for this month */
if ( (day = day%7) == 0 ) day = 7; /* correct 0 to 7 */
return ( day );
}
/************************************************************************/
/* leap */
/* Find leap years. */
/* Returns 0 - Not a leap year. */
/* 1 - leap year. */
/************************************************************************/
int leap(int year)
{
/*
A leap year follows the following rules:
if divisable by 4 and not 100 its a leap year.
if divisable by 400 it is a leap year.
*/
if ( (year%4 == FALSE && year%100 != FALSE) || year%400 == FALSE )
{
days_in_month[2] = 29;
return(1); /* leap year */
}
else
{
days_in_month[2] = 28;
return(0); /* NOT a leap year */
}
}
|
