c语言求等差数列第n项

Question

有一等差数列，输入该数列的首项、公差和项数，.求出这个数列的第 n项的值

Answer 1

#include<stdio.h>
int main(){
    int a1,d,a2, n,i;
    scanf("%d %d %d",&a1,&d,&n);
    for(i=2;i<=n;i++){
        a2=a1+d;
        a1=a2;
    }
    printf("%d",a2);
    return 0;
}