calculation from rows and columns

I am new to C, I have a problem that I can't figure it out.

I need the user to input three times 2 type of data: net and rate

I have to calculate tax=net x rate

amountdue=net + tax

I have to put all this data in a table form

net rate tax amount due

xxxx xxxx xxxx xxxxxx

xxxx xxxx xxxx xxxxxx

xxxx xxxx xxxx xxxxxx

then add all columns

I have to use scanf

how can I get the program to remember all inputs and put them in a table form with the right calculation

This is what i did so far but it is not working:

#include <stdio.h>

int main(void)

{

float net;

float rate;

float tax,amtdue;

int k;

char c1[130];

char c2[130];

tax=net*rate;

amtdue=net+tax;

for (k=0;k<3;k++)

{

printf("Input Net: ");

sscanf(c1,"%f", &net);

printf("Input Rate: ");

sscanf(c2,"%f", &rate);

printf("\nnet rate tax amtdue\n");

printf("%0.2f %0.3f ", net,rate);

printf("%0.2f $%0.2f\n", tax,amtdue);

}

return 0;

}

thanks............

JJ