5.2 高精度运算 六月飞雪

5.2.1   小学生算术    http://poj.grids.cn/practice/2562/

# include <stdio.h>

int main () {

    int a, b;
    while (scanf("%d %d", &a, &b) == 2) {
        if (!a && !b) break;
        int c = 0, ans = 0;
        for (int i = 9; i>=0; i--) {
            c = (a%10 + b%10 + c) >9 ? 1 : 0;
            ans += c;
            a /= 10; b /= 10;
        }
        if (!ans) printf("No ");
        else printf("%d ", ans);
        printf("carry operation");
        if (ans>1) putchar('s');
        printf(".\n");
    }

    return 0;
}

5.2.2  阶乘的精确值  （未找到原题网址）

# include <stdio.h>
# include <string.h>

const int maxn = 2600;
int a[2600];

int main () {

    int n;
    while (scanf("%d", &n) != EOF) {
        memset(a, 0, sizeof(a));
        a[0] = 1;
        int i;
        for (i = 2; i <= n; ++i) {
            int c = 0, s;
            for (int j = 0; j < maxn; ++j) {
                s = a[j]*i+c;
                a[j] = s % 10;
                c = s / 10;
            }
        }
        for (i = maxn-1; i >= 0; --i)
            if (a[i]) break;
        for (; i >= 0; i--)
            printf("%d", a[i]);
        puts("");
    }

    return 0;
}