下面是一个使用C语言实现等差数列求和的程序示例：
#include <stdio.h>
int main() {
int firstTerm, commonDifference, n, sum = 0;
// 输入等差数列的首项、公差和项数
printf("Enter the first term of the arithmetic sequence: ");
scanf("%d", &firstTerm);
printf("Enter the common difference of the arithmetic sequence: ");
scanf("%d", &commonDifference);
printf("Enter the number of terms in the arithmetic sequence: ");
scanf("%d", &n);
// 计算等差数列的和
sum = n * (2 * firstTerm + (n - 1) * commonDifference) / 2;
// 输出结果
printf("The sum of the arithmetic sequence is: %d\n", sum);
return 0;
}
通过输入等差数列的首项、公差和项数，该程序将计算出等差数列的和并输出结果。
