用C语言实现一个首项为1公差为1,项数为100的等差数列的求和
#include <stdio.h>
int main(void){
int a1=1; //首项
int d=1; //公差
int n=100; //项数
//https://baike.baidu.com/item/%E7%AD%89%E5%B7%AE%E6%95%B0%E5%88%97%E6%B1%82%E5%92%8C%E5%85%AC%E5%BC%8F/7527418?fr=aladdin
int sn= n*a1+n*(n-1)*d/2; //等差数列前n项的和,利用等差数列求和公式求和即可
//double sn2 = 1.0*n*a1+n*(n-1)*d/2;
//https://www.zxgj.cn/g/dengcha
printf("首项为%d,公差为%d的等差数列的前%d项之和是%d.\n",a1,d,n,sn);
// printf("首项为%d,公差为%d的等差数列的前%d项之和是%lf.\n",a1,d,n,sn2);
return 0;
}