202 - Repeating Decimals

歡迎folk或者star個人repo：https://github.com/guopeiming/algorithm-training，天天更新一道oj入門紫皮書上的題目或者oj、LeetCode，持續更新中

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

using namespace std;

int isExist(int* list, int size, int val);

int main(){
    int m, n, divided[5000], count, idx, flag;
    char decimal[5000];
    while(scanf("%d%d", &m, &n) != EOF){
        count = 0, idx = -1;
        memset((void *)divided, '\0', 500);
        memset(decimal, '\0', 500);
        printf("%d/%d = %d.", m, n, m / n);
        m = m % n;
        while(true){
            m = m * 10;
            idx = isExist(divided, count, m);
            if(idx != -1){
                break;
            }
            divided[count] = m;
            decimal[count] = (m / n) + '0';
            m = m % n;
            count++;
        }
        for(int i = 0; i < idx; ++i){
            if(i >= 50){
                break;
            }
            printf("%c", decimal[i]);
        }
        printf("(");
        for(int i = idx; i < count; ++i){
            if(i >= 50){
                printf("...");
                break;
            }
            printf("%c", decimal[i]);
        } 
        printf(")\n");
        printf("   %d = number of digits in repeating cycle\n\n", count - idx);
    }
    

}

int isExist(int* list, int size, int val){
    for(int i = 0; i < size; ++i){
        if(list[i] == val){
            return i;
        }
    }
    return -1;
}

// Sample Input
// 76 25
// 5 43
// 1 397

// Sample Output
// 76/25 = 3.04(0)
// 1 = number of digits in repeating cycle
// 5/43 = 0.(116279069767441860465)
// 21 = number of digits in repeating cycle
// 1/397 = 0.(00251889168765743073047858942065491183879093198992...)
// 99 = number of digits in repeating cycle

//https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=830&page=show_problem&problem=138

//仍是要注意整除與取餘在數字運算中的重要做用
//代碼能力！！！