Two easy vector questions.

Hello everyone. My questions are the following:

1) In a program, different values to a vector are given(e.g.: vector[1]=3; vector[2]=5; ...)

Declaration: int vector[5]={1,5,6,7,2};
And at the time of saving the info into a text file it would be something like this:

Code:

fprintf(fp,"%d %d %d %d", vector[1], vector[2], vector[3], vector[4])

and the fscanf:

Code:

fscanf(fp,"%d %d %d %d", &vector[1], &vector[2], &vector[3], &vector[4])

Imagine that it is a longer vector, then it would be a mess.

Can there be written something like this?:

Code:

fprintf(fp,"%d %d %d %d", vector[i])

fscanf(fp,"%d %d %d %d", &vector[i])

2) I've heard around that there is a command or statement used to find values in a vector. Maybe:

Code:

while(5 in vector){printf("There is a 5 in the vector.");}

But couldn't figure out how this is. Any help would be apreciated, if something isn't clear tell me, thanks.

What is your declaration of vector?

Originally Posted by Salem

What is your declaration of vector?

I've added it to main post.

Arrays in C start at 0. In your code you are trying to write/read 1 past the end of your array.

One more thing, use the code tags ONLY for code, not your entire post.

Originally Posted by Salem

One more thing, use the code tags ONLY for code, not your entire post.

Took them off.

Originally Posted by jimblumberg

Arrays in C start at 0. In your code you are trying to write/read 1 past the end of your array.

Well, yes, the declaration should be a vector[5] you are right, but anyways the question doesn't have to do with that... I've put the declaration in the main post. Thanks for the reminder anyways.

Originally Posted by Pecado

Can there be written something like this?:

Code:

fprintf(fp,"%d %d %d %d", vector[i])

fscanf(fp,"%d %d %d %d", &vector[i])

No. You can write a function to do this, though.

2) I've heard around that there is a command or statement used to find values in a vector. Maybe:

Code:

while(5 in vector){printf("There is a 5 in the vector.");}

There is no such thing. Again, a function can easily be written that does this.

You can search for a single byte in an array, so for the special case of an array of character type, there's strchr() or memchr() (depending on whether it's a string or not).

Originally Posted by Pecado

Declaration: int vector[5]={1,5,6,7,2};
And at the time of saving the info into a text file it would be something like this:

Code:

fprintf(fp,"%d %d %d %d", vector[1], vector[2], vector[3], vector[4])

Yep, that would write "5 6 7 2" to your file. (You don't get 1 because vector[0] is 1 and vector[1] is 5.

Originally Posted by Pecado

and the fscanf:

Code:

fscanf(fp,"%d %d %d %d", &vector[1], &vector[2], &vector[3], &vector[4])

That would be reading four integers from the file and storing them in vector[1] to vector[4] (Although what happens to vector[0]?)

Originally Posted by Pecado

Can there be written something like this?:

Code:

fprintf(fp,"%d %d %d %d", vector[i])

fscanf(fp,"%d %d %d %d", &vector[i])

I would go with something like

Code:

	for(int i = 0; i < VECTOR_SIZE; ++i)
		fprint(fp, "%d ", vector[i]);

	for(int i = 0; i < VECTOR_SIZE; ++i)
		fscanf(fp, "%d ", &vector[i]); // Or if you want to be fancy: fscanf(fp, "%d ", vector+i);

Originally Posted by Pecado

2) I've heard around that there is a command or statement used to find values in a vector. Maybe:

Code:

while(5 in vector){printf("There is a 5 in the vector.");}

No such command or language construct. I don't really know what you want, but you could have the following:

Code:

int find(int* vector, int size)
{
	for(int i = 0; i < size; ++i)
	{
		if(vector[i] == value) // Where value is what we are looking for
		{
			printf("The value %d exists in vector. First occurrence at vector[%d]\n", value, i);
			return 1;
		}
	}
	return 0;
}

Thank you "cas" and QuadraticFighte".

Regarding the first, I've decided to do it the old fashioned way as I have many vectors and would rather not have so many for's.

And for the second one, I don't know why I didn't think of a for construction. But thanks again.