>[info]求s=a+aa+aaa+aaaa+aa...a的值，最后一次n个a ~~~C #include <stdio.h> int main() { int s=0,a,n,t; printf("input a and n\n"); scanf("%d%d",&a, &n); t=a; while(n>0) { s+=t; a*=10; t+=a; n--; } printf("%d\n", s); return 0; } ~~~