C 程序：將二進制數轉換為八進制數 · BeginnersBook 中文系列教程

# C 程序：將二進制轉換為八進制數 > 原文： [https://beginnersbook.com/2017/09/c-program-to-convert-binary-to-octal-number-system/](https://beginnersbook.com/2017/09/c-program-to-convert-binary-to-octal-number-system/) 該 C 程序將二進制數轉換為等效的八進制數。 ## 示例：將二進制轉換為八進制的程序在該程序中，要求用戶輸入二進制數，然后程序通過調用用戶定義的函數將該二進制數轉換為八進制數。要理解這個程序，您應該熟悉以下 [C 編程](https://beginnersbook.com/2014/01/c-tutorial-for-beginners-with-examples/)概念： 1. [C - `while`循環](https://beginnersbook.com/2014/01/c-while-loop/) 2. [C - 函數](https://beginnersbook.com/2014/01/c-functions-examples/) ```c #include <stdio.h> #include <math.h> //This function converts binary number to octal number int binaryToOctal(long binarynum) { int octalnum = 0, decimalnum = 0, i = 0; /* This while loop converts binary number "binarynum" to the * decimal number "decimalnum" */ while(binarynum != 0) { decimalnum = decimalnum + (binarynum%10) * pow(2,i); i++; binarynum = binarynum / 10; } //i is re-initialized i = 1; /* This loop converts the decimal number "decimalnum" to the octal * number "octalnum" */ while (decimalnum != 0) { octalnum = octalnum + (decimalnum % 8) * i; decimalnum = decimalnum / 8; i = i * 10; } //Returning the octal number that we got from binary number return octalnum; } int main() { long binarynum; printf("Enter a binary number: "); scanf("%ld", &binarynum); // calling the function here printf("Equivalent octal value: %d", binaryToOctal(binarynum)); return 0; } ``` **輸出：** ```c Enter a binary number: 111001 Equivalent octal value: 71 ``` 在這個程序中，我們首先將輸入的二進制數轉換為十進制數，然后我們將該十進制數轉換為八進制數。看看這些相關的 C 程序： 1. [C 程序：將二進制轉換為十進制](https://beginnersbook.com/2015/02/c-program-to-convert-binary-number-to-decimal-number/) 2. [C 程序：將十進制數轉換為二進制數](https://beginnersbook.com/2017/09/c-program-to-convert-decimal-number-to-binary-number/) 3. [C 程序：將八進制數轉換為二進制數](https://beginnersbook.com/2017/09/c-program-to-convert-octal-number-to-binary-number/) 4. [C 程序：將小寫字符串轉換為大寫](https://beginnersbook.com/2015/02/c-program-to-convert-lowercase-string-to-uppercase-string/) 5. [C 程序：將大寫字符串轉換為小寫](https://beginnersbook.com/2015/02/c-program-to-convert-uppercase-string-to-lowercase-string/)