C 語言實例 - 判斷Armstrong數(阿姆斯壯數)
Armstrong 數,就是n位數的各位數的n次方之和等於該數,如:
153=1^3+5^3+3^3 1634=1^4+6^4+3^4+4^4
實例
#include <stdio.h>
int main()
{
    int number, originalNumber, remainder, result = 0;
    printf("輸入三位數: ");
    scanf("%d", &number);
    originalNumber = number;
    while (originalNumber != 0)
    {
        remainder = originalNumber%10;
        result += remainder*remainder*remainder;
        originalNumber /= 10;
    }
    if(result == number)
        printf("%d 是 Armstrong 數",number);
    else
        printf("%d 不是 Armstrong 數",number);
    return 0;
}
運行結果:
輸入三位數: 371 371 是 Armstrong
實例 - 兩數之間的 Armstrong 數
#include <stdio.h>
#include <math.h>
int main()
{
    int low, high, i, temp1, temp2, remainder, n = 0, result = 0;
    printf("輸入兩個整數: ");
    scanf("%d %d", &low, &high);
    printf("%d 和 %d 之間的 Armstrong 數為: ", low, high);
    for(i = low + 1; i < high; ++i)
    {
        temp2 = i;
        temp1 = i;
        // 計算
        while (temp1 != 0)
        {
            temp1 /= 10;
            ++n;
        }
        while (temp2 != 0)
        {
            remainder = temp2 % 10;
            result += pow(remainder, n);
            temp2 /= 10;
        }
        if (result == i) {
            printf("%d ", i);
        }
        n = 0;
        result = 0;
    }
    return 0;
}
運行結果:
輸入兩個整數: 100 1000 100 和 1000 之間的 Armstrong 數為: 153 370 371 407
實例 - 使用函數判斷Armstrong 數
#include <stdio.h>
#include <math.h>
int checkPrimeNumber(int n);
int checkArmstrongNumber(int n);
int main()
{
    int n, flag;
    printf("輸入正整數: ");
    scanf("%d", &n);
    // 檢測素數
    flag = checkPrimeNumber(n);
    if (flag == 1)
        printf("%d 是素數。\n", n);
    else
        printf("%d 不是素數\n", n);
    // 檢測 Armstrong 數
    flag = checkArmstrongNumber(n);
    if (flag == 1)
        printf("%d 是 Armstrong 數。", n);
    else
        printf("%d 不是 Armstrong 數。",n);
    return 0;
}
int checkPrimeNumber(int n)
{
    int i, flag = 1;
    for(i=2; i<=n/2; ++i)
    {
    // 非素數條件
        if(n%i == 0)
        {
            flag = 0;
            break;
        }
    }
    return flag;
}
int checkArmstrongNumber(int number)
{
    int originalNumber, remainder, result = 0, n = 0, flag;
    originalNumber = number;
    while (originalNumber != 0)
    {
        originalNumber /= 10;
        ++n;
    }
    originalNumber = number;
    while (originalNumber != 0)
    {
        remainder = originalNumber%10;
        result += pow(remainder, n);
        originalNumber /= 10;
    }
    // 判斷條件
    if(result == number)
        flag = 1;
    else
        flag = 0;
    return flag;
}
輸出結果為:
輸入正整數: 371 371 不是素數 371 是 Armstrong 數。

 C 語言實例