| 1 | char dayw[] = { |
| 2 | " S M Tu W Th F S" |
| 3 | }; |
| 4 | char *smon[]= { |
| 5 | "January", "February", "March", "April", |
| 6 | "May", "June", "July", "August", |
| 7 | "September", "October", "November", "December", |
| 8 | }; |
| 9 | char string[432]; |
| 10 | main(argc, argv) |
| 11 | char *argv[]; |
| 12 | { |
| 13 | register y, i, j; |
| 14 | int m; |
| 15 | |
| 16 | if(argc < 2) { |
| 17 | printf("usage: cal [month] year\n"); |
| 18 | exit(0); |
| 19 | } |
| 20 | if(argc == 2) |
| 21 | goto xlong; |
| 22 | |
| 23 | /* |
| 24 | * print out just month |
| 25 | */ |
| 26 | |
| 27 | m = number(argv[1]); |
| 28 | if(m<1 || m>12) |
| 29 | goto badarg; |
| 30 | y = number(argv[2]); |
| 31 | if(y<1 || y>9999) |
| 32 | goto badarg; |
| 33 | printf(" %s %u\n", smon[m-1], y); |
| 34 | printf("%s\n", dayw); |
| 35 | cal(m, y, string, 24); |
| 36 | for(i=0; i<6*24; i+=24) |
| 37 | pstr(string+i, 24); |
| 38 | exit(0); |
| 39 | |
| 40 | /* |
| 41 | * print out complete year |
| 42 | */ |
| 43 | |
| 44 | xlong: |
| 45 | y = number(argv[1]); |
| 46 | if(y<1 || y>9999) |
| 47 | goto badarg; |
| 48 | printf("\n\n\n"); |
| 49 | printf(" %u\n", y); |
| 50 | printf("\n"); |
| 51 | for(i=0; i<12; i+=3) { |
| 52 | for(j=0; j<6*72; j++) |
| 53 | string[j] = '\0'; |
| 54 | printf(" %.3s", smon[i]); |
| 55 | printf(" %.3s", smon[i+1]); |
| 56 | printf(" %.3s\n", smon[i+2]); |
| 57 | printf("%s %s %s\n", dayw, dayw, dayw); |
| 58 | cal(i+1, y, string, 72); |
| 59 | cal(i+2, y, string+23, 72); |
| 60 | cal(i+3, y, string+46, 72); |
| 61 | for(j=0; j<6*72; j+=72) |
| 62 | pstr(string+j, 72); |
| 63 | } |
| 64 | printf("\n\n\n"); |
| 65 | exit(0); |
| 66 | |
| 67 | badarg: |
| 68 | printf("Bad argument\n"); |
| 69 | } |
| 70 | |
| 71 | number(str) |
| 72 | char *str; |
| 73 | { |
| 74 | register n, c; |
| 75 | register char *s; |
| 76 | |
| 77 | n = 0; |
| 78 | s = str; |
| 79 | while(c = *s++) { |
| 80 | if(c<'0' || c>'9') |
| 81 | return(0); |
| 82 | n = n*10 + c-'0'; |
| 83 | } |
| 84 | return(n); |
| 85 | } |
| 86 | |
| 87 | pstr(str, n) |
| 88 | char *str; |
| 89 | { |
| 90 | register i; |
| 91 | register char *s; |
| 92 | |
| 93 | s = str; |
| 94 | i = n; |
| 95 | while(i--) |
| 96 | if(*s++ == '\0') |
| 97 | s[-1] = ' '; |
| 98 | i = n+1; |
| 99 | while(i--) |
| 100 | if(*--s != ' ') |
| 101 | break; |
| 102 | s[1] = '\0'; |
| 103 | printf("%s\n", str); |
| 104 | } |
| 105 | |
| 106 | char mon[] = { |
| 107 | 0, |
| 108 | 31, 29, 31, 30, |
| 109 | 31, 30, 31, 31, |
| 110 | 30, 31, 30, 31, |
| 111 | }; |
| 112 | |
| 113 | cal(m, y, p, w) |
| 114 | char *p; |
| 115 | { |
| 116 | register d, i; |
| 117 | register char *s; |
| 118 | |
| 119 | s = p; |
| 120 | d = jan1(y); |
| 121 | mon[2] = 29; |
| 122 | mon[9] = 30; |
| 123 | |
| 124 | switch((jan1(y+1)+7-d)%7) { |
| 125 | |
| 126 | /* |
| 127 | * non-leap year |
| 128 | */ |
| 129 | case 1: |
| 130 | mon[2] = 28; |
| 131 | break; |
| 132 | |
| 133 | /* |
| 134 | * 1752 |
| 135 | */ |
| 136 | default: |
| 137 | mon[9] = 19; |
| 138 | break; |
| 139 | |
| 140 | /* |
| 141 | * leap year |
| 142 | */ |
| 143 | case 2: |
| 144 | ; |
| 145 | } |
| 146 | for(i=1; i<m; i++) |
| 147 | d += mon[i]; |
| 148 | d %= 7; |
| 149 | s += 3*d; |
| 150 | for(i=1; i<=mon[m]; i++) { |
| 151 | if(i==3 && mon[m]==19) { |
| 152 | i += 11; |
| 153 | mon[m] += 11; |
| 154 | } |
| 155 | if(i > 9) |
| 156 | *s = i/10+'0'; |
| 157 | s++; |
| 158 | *s++ = i%10+'0'; |
| 159 | s++; |
| 160 | if(++d == 7) { |
| 161 | d = 0; |
| 162 | s = p+w; |
| 163 | p = s; |
| 164 | } |
| 165 | } |
| 166 | } |
| 167 | |
| 168 | /* |
| 169 | * return day of the week |
| 170 | * of jan 1 of given year |
| 171 | */ |
| 172 | |
| 173 | jan1(yr) |
| 174 | { |
| 175 | register y, d; |
| 176 | |
| 177 | /* |
| 178 | * normal gregorian calendar |
| 179 | * one extra day per four years |
| 180 | */ |
| 181 | |
| 182 | y = yr; |
| 183 | d = 4+y+(y+3)/4; |
| 184 | |
| 185 | /* |
| 186 | * julian calendar |
| 187 | * regular gregorian |
| 188 | * less three days per 400 |
| 189 | */ |
| 190 | |
| 191 | if(y > 1800) { |
| 192 | d -= (y-1701)/100; |
| 193 | d += (y-1601)/400; |
| 194 | } |
| 195 | |
| 196 | /* |
| 197 | * great calendar changeover instant |
| 198 | */ |
| 199 | |
| 200 | if(y > 1752) |
| 201 | d += 3; |
| 202 | |
| 203 | return(d%7); |
| 204 | } |