int main (void)
{
   
    int          t_ct;
    double       time, x;
    int          limit;
   
   
    printf("Enter the number of terms you want: ");
    scanf ("%d",&limit);
    for(time=0,x=1,t_ct=1;   t_ct<=limit;     t_ct++,x *=2.0 )    /*   t_ct = t_ct * 2.0  */
    {
        time += 1.0/x;                                            //   time = tinme + 1.0/x;
        printf("time = %f when terms = %d.\n",time,t_ct);
        
        
        
        
    }
}
   



    for(time=0,x=1,t_ct=1;   t_ct<=limit;     t_ct++,x *=2.0 )  求帮忙指点下这行 有点不太明白

Enter the number of terms you want: 15
time = 1.000000 when terms = 1.
time = 1.500000 when terms = 2.
time = 1.750000 when terms = 3.
time = 1.875000 when terms = 4.
time = 1.937500 when terms = 5.
time = 1.968750 when terms = 6.
time = 1.984375 when terms = 7.
time = 1.992188 when terms = 8.
time = 1.996094 when terms = 9.
time = 1.998047 when terms = 10.
time = 1.999023 when terms = 11.
time = 1.999512 when terms = 12.
time = 1.999756 when terms = 13.
time = 1.999878 when terms = 14.
time = 1.999939 when terms = 15.

--------------------------------
Process exited with return value 0
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