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

int main(){

  long int decimalNumber,quotient;
  int binaryNumber[100],i=1,j;

  printf("Enter any decimal number: ");
  scanf("%d",&decimalNumber);

  quotient = decimalNumber;

  if(quotient!=0){
      binaryNumber[i++]= quotient % 2;
      quotient = quotient / 2;
  }

  printf("Equivalent octal value of decimal number %d: ",decimalNumber);
  for(j = i -1 ;j> 0;j--)
      printf("%d",binaryNumber[j]);

  system("pause");
  return 0;
}

-----------------------------------------------------------------------
請各位幫忙看一下 為什麼輸出的結果不是二進制??
感謝各位高手的幫忙!!!

二进制一般都用字符串来表示的

long类型对应的是%ld
if(quotient!=0) 应该是 while(quotient!=0)

从1开始计数是很恶心的行为

if(quotient!=0)
把这一语代码中的if 改为  while  就行了

楼上正解

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

int main(){

  long int decimalNumber,quotient;
  int binaryNumber[100],i=1,j;

  printf("Enter any decimal number: ");
  scanf("%d",&decimalNumber);

  quotient = decimalNumber;

  while(quotient!=0)
  {
      binaryNumber[i++]= quotient % 2;
      quotient = quotient / 2;
  }

  printf("Equivalent octal value of decimal number %d: \n",decimalNumber);
  for(j = i -1 ;j> 0;j--)
      printf("%d\n",binaryNumber[j]);

  system("pause");
  return 0;                       我帮你修改了，你现在看一下吧
}