Thread: C programming question

So, what is your code, your test input, expected output, and actual output?

this is the code ive been working
Input:

Input the start time of the call: 1800
Input the length of call in minutes : 61

Output :

Gross cost : 488.00
Net cost : 430.56
that should be the output but my code outputs this
Output :

Gross cost : 488.00
Net cost : 431.39

Code:

#include<stdio.h>#include<conio.h>


int main()
{
    int time,min;
    float priceperminute=8, discount=0, grosscost=0, netcost=0;
    
    printf("Input the start time of the call:");
    scanf("%d", &time);
    printf("Input the length of the call in minutes:");
    scanf("%d", &min);
    
    grosscost=min*priceperminute;
    
    if(time>=800 && time<=1800)
    {
        netcost=grosscost;
 }
    else
    netcost=grosscost*0.5;
    
    if (min>=60)
    netcost-= netcost*0.15;


    float tax= netcost*4/100;
    netcost=netcost+tax;


    printf("Grosscost:%.2f",grosscost);
    printf("\nNetcost:%.2f", netcost);
    return 0;    
}

Have you tried to work it out by hand?

I ran the code through the debugger one line at a time.

The individual values of netcost, discount and tax all seem fine.
If you want a different answer, it needs a different calculation.

Code:

$ gcc -g -Wall foo.c
foo.c: In function ‘main’:
foo.c:6:29: warning: unused variable ‘discount’ [-Wunused-variable]
   float priceperminute = 8, discount = 0, grosscost = 0, netcost = 0;
                             ^
$ gdb -q ./a.out
Reading symbols from ./a.out...done.
(gdb) b main
Breakpoint 1 at 0x4005fe: file foo.c, line 4.
(gdb) run
Starting program: ./a.out 

Breakpoint 1, main () at foo.c:4
4	{
(gdb) n
6	  float priceperminute = 8, discount = 0, grosscost = 0, netcost = 0;
(gdb) 
8	  printf("Input the start time of the call:");
(gdb) 
9	  scanf("%d", &time);
(gdb) 
Input the start time of the call:1800
10	  printf("Input the length of the call in minutes:");
(gdb) 
11	  scanf("%d", &min);
(gdb) 
Input the length of the call in minutes:61
13	  grosscost = min * priceperminute;
(gdb) 
15	  if (time >= 800 && time <= 1800) {
(gdb) p grosscost
$1 = 488
(gdb) n
16	    netcost = grosscost;
(gdb) 
20	  if (min >= 60)
(gdb) 
21	    netcost -= netcost * 0.15;
(gdb) 
23	  float tax = netcost * 4.0 / 100;
(gdb) p netcost
$2 = 414.799988
(gdb) n
24	  netcost = netcost + tax;
(gdb) p tax
$3 = 16.5919991
(gdb) n
26	  printf("Grosscost:%.2f", grosscost);
(gdb) p grosscost
$4 = 488
(gdb) n
27	  printf("\nNetcost:%.2f", netcost);
(gdb) p netcost
$5 = 431.391998
(gdb)