Some help on how to complete this program in C.

[KatiNescher9]

I'm very very new at C programming/writing and I'm so confused, I have no idea what I'm doing. I was given this problem to do and I'm so confused on what to put on the Printf() statement... I don't know what kind of set up it should have either. What should be on the printf(.....) statement to calculate 123 seconds into minutes and seconds (2 minutes and 3 seconds.)
Please help:

/* Convert seconds to minutes and seconds. */
#include<stdio.h>

int main(void)
{
int input_value, minutes, seconds;

printf("Input the number of seconds:");
scanf("%d", &input_value);
minutes=input_value / 60;
seconds=input_value % 60;
printf(.....);
return 0;
}


2)I have two other I don't quite understand, if someone can please give me some help, and explain just the basics of the codes, but if not the answers are fine:
Write an interactive program that asks the user to input the length and width of a rectangular lawn. The dimensions should be in yards. Your program should compute the area of the lawn in square yard, square feet, and square inches. Print all the information neatly on the scree. Use the following declaration:

int cv_factor = 36 * 36; /* conversion:sq in per yrd */
or
int cv_factor= 1296; /* conversion: sq in per yrd */

3)Here is a part of an interactive program that computes the value of some coins. The user is asked to input the number of half dollars, quarters, dimes, and so on.

#include<stdio.h>

int main(void)
{
int h, /* number of half dollars */
q, /* number of quarters */
d, /*number of dimes */
n, /*number of nickels */
p; /*number of pennies*/
.....

printf("Value of your change will be computed. \n\n");
printf("How many half dollars do you have?");
scanf("%d", &h);
printf("How many quarters do you have?");
scanf("%d" , &q);

Complete the program, causing it to print out relevant information. For example, you may want to create out that looks like this:

You entered: 0 half dollars
3 quarters
2 dimes
17 nickels
1 pennies
The values of your 23 coins is equivalent to 181 pennies.

[KatiNescher9]

Thank Ya'll for future answers.

[Banfa]

1. You need a printf statement to output integers, you use %d in a printf statement to output an integer so you need something like

printf("%d minutes %d seconds", minutes, seconds);
 

However there is much much more to printf format strings, I suggest you search the web (for "printf format string"), wikipedia has a reasonable page on the subject.

3. This is really just asking you to do fairly simple maths to compute the result. The first step to working out how to do this is to do the calculation on paper, then once you can see how you did the calculation you just write code to get the computer to do the same thing.

e.g.

I have
1 50p coin
2 20p coins
0 10p coins
3 5p coins
4 2p coins
1 1p coins

How much money do I have in pence

1 x 50 = 50
2 x 20 = 40
0 x 10 = 10
3 x 5 = 15
4 x 2 = 8
1 x 1 = 1

50 + 40 + 10 + 15 + 8 + 1 = 124

Answer: 124p

Use of the addition, multiplication and assignment operators are covered by most basic tutorials/notes/text books.

2. This is a similar, if simpler maths problem.

Area = length * width.
Input length;
Input width;
Calculate area;
Convert area to alternate unit by times by a conversion factor.

[KatiNescher9]

Ok Thank You. It really helped.

[donbock]

I would add a newline to the end of Banfa's printf format string like this:

printf("%d minutes %d seconds\n", minutes, seconds);

printf sends text to stdout (standard output). In some compilers, stdout is buffered. That means, among other things, that all printf output text is buffered (held) by the operating system until a newline is printed.