任何人都可以帮助我解决以下 C++ 代码中的问题吗？ 该程序不提供任何输出

Question

The below code has been written aiming to generate all the armstrong* numbers below 1000.

*armstrong numbers:An Armstrong number of three digits is an integer such that the sum of the cubes of its digits is equal to the number itself. For example, 371 is an Armstrong number since 3^3 + 7^3 + 1^3 = 371.

#include<iostream>
using namespace std;
int main()
{
 int n,sum=0,digit,a,b;
 for(n;n<1000;n++)
  {
  a=n;
  b=n;
  for(b;b>=0;b/10)
  {
   digit=b%10;
   sum+=(digit*digit*digit);
  }
   (sum==a)?cout<<a:cout<<" ";
 }
 return 0;
}

Answer 1

n is initially an undefined value. You'll need to set it to 0 before the for loop.

Also, b isn't being changed. Did you mean b /= 10 rather than b / 10 ?

Answer 2

I'd suggest to structure the code to make it easier to read, eg by introducing a function bool isArmstrong(int number) ; distinguish logic from using the logic; never let variables be uninitialised; introduce variables right there where they are used; give variables a meaning by using names other than a , b ;

Then things like not initialized variables or infinite loops become much more apparent:

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

bool isArmstrong(int number) {

    int cubeSum = 0;
    for (int remainingPortion = number; remainingPortion > 0; remainingPortion/=10) {
        int digit = remainingPortion % 10;
        cubeSum += digit*digit*digit;
    }
    return (cubeSum == number);
}

int main() {

    for (int number = 0; number < 1000; number++)
    {
        if (isArmstrong(number))
            printf("%d is an armstrong number\n", number);
    }

    return 0;
}