#include <stdio.h>

void cal(int y)
{
    int  m, d, w, i, z;  char x[12][6][7] = { 0 };

    w = (y + (y-1)/4 - (y-1)/100 + (y-1)/400) % 7;
    for (m = 1; m <= 12; m++) {
        z = (m==2) ? 28+(y%4==0 && y%100 || y%400==0) : 30+(0x15aa>>m&1);
        for (i = 0, d = 1; d <= z; d++) {
            x[m-1][i][w] = d;
            if (++w == 7) w = 0, i++;
        }
    }
    printf("%36d年\n\n", y);
    for (m = 1; m <= 12; m += 3) {
        #define WEEK  " 日 月 火 水 木 金 土   "
        printf("%11d月%22d月%22d月\n" WEEK WEEK WEEK "\n", m, m+1, m+2);
        for (i = 0; i < 6; i++)
            for (z = -1; z < 2; z++) {
                for (w = 0; w < 7; w++)
                    printf(x[m+z][i][w] ? "%3d" : "   ", x[m+z][i][w]);
                printf(z==1 ? "\n" : "   ");
            }
        puts("");
    }
}

int main(void)
{
    int y;

    printf("カレンダーを表示する年を入力してください。");
    if (scanf("%d", &y) == 1) cal(y);
    return 0;
}

    printf("%36d年\n\n", y);
    for (m = 1; m <= 12; m += 3) {
        #define WEEK  " \33[31m日\33[37m 月 火 水 木 金 \33[33m土\33[37m   "
        printf("%11d月%22d月%22d月\n" WEEK WEEK WEEK "\n", m, m+1, m+2);
        for (i = 0; i < 6; i++)
            for (z = -1; z < 2; z++) {
                for (w = 0; w < 7; w++) {
                    printf(!w ? "\33[31m" : (w == 6 ? "\33[33m" : "\33[37m"));
                    printf(x[m+z][i][w] ? "%3d" : "   ", x[m+z][i][w]);
                }
                printf(z==1 ? "\n" : "   ");
            }
        puts("");
        printf("\33[37m");
    }

    printf("%36d年\n\n", y);
    for (m = 1; m <= 12; m += 3) {
        #define WEEK  " \33[31m日\33[37m 月 火 水 木 金 \33[33m土\33[37m   "
        printf("%11d月%22d月%22d月\n" WEEK WEEK WEEK "\n", m, m+1, m+2);
        for (i = 0; i < 6; i++)
            for (z = -1; z < 2; z++) {
                for (w = 0; w < 7; w++) {
                    printf(!w ? "\33[31m" : (w == 6 ? "\33[33m" : "\33[37m"));
                    printf(x[m+z][i][w] ? "%3d" : "   ", x[m+z][i][w]);
                }
                printf(z==1 ? "\n" : "   ");
            }
        puts("");
        printf("\33[37m");    /* ←ここ忘れませんでしたか？ */
    }