求SN=a+aa+aaa+......+aaa....
#include "stdio.h"
main()
{
int a,n,i=1;
double sn,tn;
for(;;)
{
scanf("%d%d",&a,&n);
if(a<10&&a>0&&n>0) break;
printf("a must between 1~9,n must bigger than 0.");
}
tn=0;
sn=0;
while(i<=n)
{
tn=tn*10+a;
sn=sn+tn;
i++;
}
printf("%f",sn);
}
#include "stdio.h"
#include "conio.h"
main()
{
int a,n,count=1;
long int sn=0,tn=0;
printf("please input a and n\n");
scanf("%d,%d",&a,&n);
printf("a=%d,n=%d\n",a,n);
while(count<=n)
{
tn=tn+a;
sn=sn+tn;
a=a*10;
++count;
}
printf("a+aa+...=%ld\n",sn);
getch();
}
参考资料：C程序100例
