I think the problem might be that your trying to return multiple values with a single call one at a time. When you use the return function, it ends that function call. Full stop. So it'll likely only get through the first number, hit return, then exit the whole function instead of continuing the loop, and since you only call pattern() once, you likely only get one value. To fix this, you could make it so instead of returning the value right away, you could store it in a list, and then return the list when its finished to print it, or better still, print the value right there instead of returning it.

Yes, an array is what I meant. Printing it in the function should be fairly straight forward, just replace return j; with printf("%d",j), like so:

#include <stdio.h>
int pattern(int);
void main()
{
int n, r;
printf("Enter the value of n:");
scanf("%d",&n);
pattern(n);
}
int pattern(int n)
{
int i, j;
for(i=1;i<=n;i++)
{
for(j=1;j<i;j++)
{
printf("%d",j);
}
}
}

In the c primer+, there is a question about units of measurement, I have copied that question below:

In the U.S. system of volume measurements, a pint is 2 cups, a cup is 8 ounces, an ounce is 2 tablespoons, and a tablespoon is 3 teaspoons. Write a program that requests a volume in cups and that displays the equivalent volumes in pints, ounces, tablespoons, and teaspoons. Why does a floating-point type make more sense for this application than an integer type?

The float type does not present any problems for me. but I tried to search these volumes of measurements on the internet, and I did not get any clear answers so I could use those values in my program.

If you have knowledge of these measurements, please explain their values?

It's simple, according to mathematics.
For example, if you got the measurement in cups, all you need to do to transform it in pinds is to divide it by 2 since a pind is specified as two cups. If you want to transform it further in ounces, you have to multiply  the cups by 8 since a ounce  is declared as eight cups.
I don't know whether those measurement units actually exist, but they could be fake for what I care, it would still be done the same regardless.

Thanks guys, now I can move on to next chapter in peace.

...until there comes a new problem.

Hello.
You do not require the second loop
Since scanf will already ask you for input twice, creating a second loop will just encrease the times of this process. Therefore, if you for instance run the second loop  2 times, you will be asked for 4 numbers.
the code should be
#include <stdio.h>
int main(void)
{
int i, n, j, sum1, sum2;
printf("Enter the pares of values to be summed:");
scanf("%d",&n);
for(i=0;i<n;i++)//this loop is for the amounts of pairs.
{
printf("enter the pares of sums:");
scanf("%d%d",&sum1,&sum2);
printf("%d\n",sum1+sum2);
}
}
In this way the program should just ask you for 2 values and then encrease the step of the loop without doubling the values to ask.

Okay, a new problem.

This time, I have to compare the two numbers, and get the minimum of two as an answer.

For example, 3<5=3

But this time, the problem is, I also have negative numbers.

For example, -5<6=-5

Now, how can I compare negative numbers?

This time I don't have any code to put here either, sorry about that.

Please note that I do know how to do that with positive numbers, but negative numbers is something which I have not dealt with two often.

It is actually verry easy, the same as with positive numbers.
int compare(int a, int b)
a<b return a?return b;
Offcourse this bit of code may be wrong, especially my use of the turnary operator, but I wrote this code the way it is because I am on the phone and don't know where the braces are, but I think I should always provide a bit of code when answering such questions .

I knew something wasn't quite right.
By the way, thank you for rembering me how to use that operator.
As I said above, I didn't write the code in a simpler way because of my phone's touchscreen keyboard.

While I haven’t work with the language, if it already excepts normal Numbers, there is no reason that the method you are using should not accept negatives.

I highly discourage use of the tirnary operator. It is trivial to make mistakes with it and makes your code harder to understand (especially with complex expressions). Just use normal if/else if/else/... as much as possible and avoid the tirnary.

Ternary is absolutely fine in certain situations. You shouldn't use it in e.g. nested if situations, it will just mess things up, but in the above situation, where a single function should just return values depending on the input and there are just two outcomes possible, ternary is fine to use. If it starts to confuse you in that specific situation, you should go back and learn it again anyway.
Best Regards.
Hijacker