C中1234能组成多少个互不相同的三位数；求s=a+aa+aaa+aaaa+aaaaa;

int main(){int i=0;int j=0;int k=0;int sum=0;int n=0;for(i=1;i<5;i++){for(j=1;j<5;j++){for(k=1;k<5;k++){if(i!=j&&j!=k&&k!=i){printf("%d%d%d ",i,j,k);sum++;}}}}if(n%10==0)printf("\n");printf("sum=%d\n",sum);return 0;}include <stdio.h>int main(){int n = 0;int a = 0;int index = 0;int sum = 0;int cur=0;printf("最多输入几项：");scanf("%d", &n);printf(" 输入一个基数：");scanf("%d", &a);for (index = 0; index < n; index++){cur = cur * 10 + a;}sum += cur;printf("sum=%d\n", sum);return 0;}