# C 程序：查找前 n 个自然数的和 > 原文： [https://beginnersbook.com/2017/10/c-program-to-find-the-sum-of-first-n-natural-numbers/](https://beginnersbook.com/2017/10/c-program-to-find-the-sum-of-first-n-natural-numbers/) 程序查找前`n`个自然数的总和。我们将看到计算自然数的总和的两个 C 程序。在第一个 C 程序中，我们使用`for`循环查找总和，在第二个程序中，我们使用`while`循环执行相同操作。 要了解这些程序，您应该熟悉以下 [C 编程](https://beginnersbook.com/2014/01/c-tutorial-for-beginners-with-examples/)概念： 1. [C 编程`for`循环](https://beginnersbook.com/2014/01/c-for-loop/) 2. [C 编程`while`循环](https://beginnersbook.com/2014/01/c-while-loop/) ## 示例 1：使用`for`循环查找自然数之和的程序 用户输入`n`的值，程序使用`for`循环计算前`n`个自然数的总和。 ```c #include <stdio.h> int main() { int n, count, sum = 0; printf("Enter the value of n(positive integer): "); scanf("%d",&n); for(count=1; count <= n; count++) { sum = sum + count; } printf("Sum of first %d natural numbers is: %d",n, sum); return 0; } ``` 输出： ```c Enter the value of n(positive integer): 6 Sum of first 6 natural numbers is: 21 ``` ## 示例 2：使用`while`循环查找自然数的总和 ```c #include <stdio.h> int main() { int n, count, sum = 0; printf("Enter the value of n(positive integer): "); scanf("%d",&n); /* When you use while loop, you have to initialize the * loop counter variable before the loop and increment * or decrement it inside the body of loop like we did * for the variable "count" */ count=1; while(count <= n){ sum = sum + count; count++; } printf("Sum of first %d natural numbers is: %d",n, sum); return 0; } ``` 输出： ```c Enter the value of n(positive integer): 7 Sum of first 7 natural numbers is: 28 ``` 看看这些相关的 C 程序： 1. [C 程序：查找数组元素之和](https://beginnersbook.com/2014/06/c-program-to-find-sum-of-array-elements-using-pointers-recursion-functions/) 2. [C 程序：相加两个数字](https://beginnersbook.com/2017/09/c-program-to-add-two-numbers/) 3. [C 程序：查找商和余数](https://beginnersbook.com/2017/09/c-program-to-find-quotient-and-remainder/) 4. [C 程序：交换两个数字](https://beginnersbook.com/2017/09/c-program-to-swap-two-numbers/) 5. [C 程序：查找数字的阶乘](https://beginnersbook.com/2014/06/c-program-to-find-factorial-of-number-using-recursion/)