Beginner: What is wrong with my code? It seems fine!

Hi there,
This is my first post.
I am new to prgramming and the C language, and was following instructions from a book to produce a simple execution. Unfortunately, it does not give me clean results when I try and compile it (with Xcode), so I was wondering if anybody here could help me solve it?

It is basic, so please do not get too in depth about it, as I only briefly understand C. Thanks.

Code:

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/* Code to calculate earnings using to variables*/

#include <stdio.h>

int main(void) {
       
        int age; /* User's age in years*/
        float hourly_wage; /* User's hourly wage in pounds. */
       
        /* Set the values*/
       
        age=40;
        hourly_wage= 6.50;
       
       
        /* Print the variable values*/
       
Printf ("You are %d years old.\n", age);
Printf ("Your hourly wage is £%0.2f. This translates into £%0.2f per year.\n", hourly_wage, hourly_wage*12*5*52);
       
       
       
        return 0;
       
}

---

This is the end of my code.


Thanks,

Shiv

P.S: This is the error I was getting:

"_Printf", referenced from:

There is no "Printf" in C, but there is "printf". C is case sensitive.

Yes,also please use code tags! http://cboard.cprogramming.com/cplus...ead-first.html

Ahhh...thanks so much mate.

Best,
Shiv

Oh and just in case you weren't aware, you can use "//" for single line comments, i.e:

// Comment

/*
This is for multiple
line comments
Although it can be used for single as well.
*/

// only exists in C99, though, but many compilers support it as a C90 extension.

Cheers, I didn't know that. I'm currently learning basic-C from a book I got out of the local library.

Best,
Shiv

You have to check out Deitel's book, there are lot of good exercises to fix sintax doubts such as the "case sensitive" issue of C.

Amazon.com: C How to Program Introducing C++ and Java (9780131426443): Harvey M. Deitel, Paul J. Deitel: Books

Also, using floats for money is a bad idea! Money is *not* floating point; it's fixed precision.

Try this:

Code:

---

#include <stdio.h>

int main() {
        float x=0.0f, i;
        for (i=0.0f; i<20; i+=0.1f) {
                printf("%f\n",x+i);
        }
        return 0;
}

---

Depending on whether you system is 32 or 64 bit, at some point you will see the expected (an increase of 0.1 at each iteration) become the unexpected:

2.500000
2.600000
2.700000
2.799999
2.899999
2.999999
3.099999
3.199999

This has to do with the nature of floating point numbers. You may think this is okay, since you are going to round it anyway, but actually the opposite it true: if you do enough arithmetic with floats like this, you can end up losing pennies.

When dealing with money, always use an int value, the number of cents, and convert it using division (and modulus for the remainder) for output:

Code:

---

int val = 532;    /* number of cents */
printf("$%d.%2d\n",val/100,val%100);

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Quote:

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Originally Posted by MK27

Also, using floats for money is a bad idea! Money is *not* floating point; it's fixed precision.

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I disagree. When calculating loans, interest, payment amount, or pension payouts, etc., money amounts are treated as high precision floating point. If you had to force each intermediate calculation to the nearest penny you'd end up with inaccurate results. Instead, rounding occurs at the very end when showing the amounts to be paid or paid out.

Quote:

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Originally Posted by nonoob

I disagree. When calculating loans, interest, payment amount, or pension payouts, etc., money amounts are treated as high precision floating point. If you had to force each intermediate calculation to the nearest penny you'd end up with inaccurate results. Instead, rounding occurs at the very end when showing the amounts to be paid or paid out.

---

In this case, money is still stored as an integer value. It's just the results of calculations that are floating point variables.

In other words, you can have something like:

Code:

---

unsigned int accrue_interest(unsigned int initial_amount)
{
    // calculate interest and return the result
}

---

The input and output are integers, but the calculations will involve some floating point arithmetic and rounding. The reasoning for keeping it integer based is so that when you have something like:

Code:

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unsigned int make_deposit(unsigned int balance, unsigned int deposit)
{
    return balance + deposit;  // Won't give you any precision issues due to using integer arithmetic.
}

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