I'm new to programming and attending a course in C. We learned how to create an array of values and it's all good. Now we have to recall a certain value from the array using scanf(). Now we didn't get explained how to do that and I guess they are expecting us to figure it out ourselves but I have now spent the whole day 'figuring out' without success. I just don't understand. Now I'm not asking to solve the problem for me but at least explain the rule and I can then write the code. I've read all about arrays in C and I understand what it is and how it works but nowhere I could find explanation about this problem. This is my sample code. I create an array with 3 variables of type int. I store 3 values using for loop. Now I need to recall for example index 1.
#include <stdio.h>
int main(void){
int values [3];
int i=0;
for (i=0; i<3; i++){
scanf("%d", &values[i]);
}
return 0;
}
Accessing a value from an array goes the same way for inserting and reading from it.
int index;
scanf("%d", &index);
printf("%d", values[index]);
Sorry, heres is the answered code. I know it's pathetically simple and it is with the help here that I finally understood.I just couldn't understand how index integer would work but I get it now. You are basically calling a memory cell to retrieve its value through an integer. Ahh, I'm so not clever.
#include <stdio.h>
int main(void){
int array [10];
int i, index=0, values=0;
for (i=0; i<10; i++){
scanf("%d", &values);
array[i] = values;
}
scanf("%d", &index);
printf("%d", array[index]);
return 0;
}
Related
I am supposed to create a code that where you you have to these things:
input the amount of rows and columns
input the sum of each row, and columns.(they don't have to be the same as long as bigger than 0.
then you have to check if the sums are correct.
I've tried doing as a long array instead and checking when each row starts as well as doing it as a matrix but we haven't learned that. I'm coding in C, and what i'm asking for is useful tools I can use when doing this. A beginner coding in C as well.
#include <stdio.h>
int main() {
int row,column;
scanf("%d %d", row, column);
int array[row][column],i;
for (i=0; i<row; i++)
return 0;
}
this is as far as i've gotten the problem is writing in a sum of one row and then comparing that.
Consider this a comment!
you should add a '&' in scanf to store the scaned value in the adresse of the variable so it would be
scanf("%d %d",&row,&column);
I am doing a simple function that returns the minimum integer from numbers given from the user(array).
However, it always print 2686916 at the end. Here is my code:
int function()
{
int ar[100];
int i;
int smallest = INT_MAX;
int nums;
int num;
int sum=0;
printf("\nenter array size\n");
scanf("%d",&num);
for(i=0;i<num;i++)
{
scanf("%d",&ar[i]);
sum=sum+ar[i];
}
if (nums <smallest){
smallest=nums;
printf("the smallest %d\n,smallest);
return 0;
}
}
I'm not sure what I'm doing wrong.
My friend, it seems you are new to C, and before you ask questions like this one you should try to follow some tutorials for C. You might try something like this.
If the question you ask is not clear or the code you post won't compile anyway it is very hard to help you out. For now this is all I can do:
int function()
{
int ar[100];
int i;
int smallest = INT_MAX;
int nums = 0; //Always Initialize your variables!
int num = 0;
int sum= 0;
printf("\nenter array size\n");
scanf("%d",&num);
for(i=0;i<num;i++)
{
scanf("%d",&ar[i]);
sum=sum+ar[i];
}
if (nums <smallest)
{
smallest=nums;
printf("the smallest %d\n",smallest);
}
return 0; //Don't put this in a place that might not be executed!
}
Now it should at least compile, it still doesn't do anything useful as far as I can see. You compare "nums", a variable you didn't use before, with the biggest value of an int, set it to the never used "nums" and print it.
You might want use "sums" or "ar[i]" in the if statement instead, and printing one of these values.(still not 100% sure what you want to do).
Some tips for next time (before you ask a question!):
Variables should always be initialized
In your code you try to use the value of "nums" before it gets a value, this might cause errors or strange results in your code.
Don't put a return in a place that might be skipped,
In your code, "nums" would be bigger than "smallest" (unlikely, bit for example), the code would skip the if statement and never reach the return.
Read your compiler warnings
The code you posted can't compile, read your errors and warnings, and fix them.
(tip) Use better variable names, using names like nums, num and sum make it easy to overlook a mistake.
I have made a dynamic array of integers in C, here is my code
#include <stdio.h>
int main(){
int count=0, i, input;
int *myarr;
myarr=(int*)malloc(4*sizeof(int));
while(1){
scanf("%d", &input);
myarr[count]=input;
count++;
if (input == -1) break;
}
for (i=0; i<count; i++){
printf("%d ", myarr[i]);
}
return 0;
}
From the code, I thought i clearly made an array of 4 integers only i.e myarr[0] up to myarr[3], how come when i insert even 10 integers, it still prints all of them, it doesn't print garbage as i thought it would after the fourth integer... Maybe i didn't understand the point of dynamic creating an array?? Make me straight please!
You should only access myarr[0] up to and including myarr[3].
Accessing any other index is undefined behaviour: it might work, it might not.
Also, myarr[count]==input looks like a typo. Did you mean myarr[count] = input? The way you have it is testing if myarr[count] equals input. Technically the way you have it is undefined behaviour for any element of myarr since you are making use of uninitialised data.
I want to add numbers to an array using scanf
What did i do wrong? it says expected an expression on the first bracket { in front of i inside the scanf...
void addScores(int a[],int *counter){
int i=0;
printf("please enter your score..");
scanf_s("%i", a[*c] = {i});
}//end add scores
I suggest:
void addScores(int *a, int count){
int i;
for(i = 0; i < count; i++) {
printf("please enter your score..");
scanf("%d", a+i);
}
}
Usage:
int main() {
int scores[6];
addScores(scores, 6);
}
a+i is not friendly to newcomer.
I suggest
scanf("%d", &a[i]);
Your code suggests that you expect that your array will be dynamically resized; but that's not what happens in C. You have to create an array of the right size upfront. Assuming that you allocated enough memory in your array for all the scores you might want to collect, the following would work:
#include <stdio.h>
int addScores(int *a, int *count) {
return scanf("%d", &a[(*count)++]);
}
int main(void) {
int scores[100];
int sCount = 0;
int sumScore = 0;
printf("enter scores followed by <return>. To finish, type Q\n");
while(addScores(scores, &sCount)>0 && sCount < 100);
printf("total number of scores entered: %d\n", --sCount);
while(sCount >= 0) sumScore += scores[sCount--];
printf("The total score is %d\n", sumScore);
}
A few things to note:
The function addScores doesn't keep track of the total count: that variable is kept in the main program
A simple mechanism for end-of-input: if a letter is entered, scanf will not find a number and return a value of 0
Simple prompts to tell the user what to do are always an essential part of any program - even a simple five-liner.
There are more compact ways of writing certain expressions in the above - but in my experience, clarity ALWAYS trumps cleverness - and the compiler will typically optimize out any apparent redundancy. Thus - don't be afraid of extra parentheses to make sure you will get what you intended.
If you do need to dynamically increase the size of your array, look at realloc. It can be used in conjunction with malloc to create arrays of variable size. But it won't work if your initial array is declared as in the above code snippet.
Testing for a return value (of addScores, and thus effectively of scanf) >0 rather than !=0 catches the case where someone types ctrl-D ("EOF") to terminate input. Thanks #chux for the suggestion!
My teacher gave an assignment to me. The question is below:=
Write a program that prompts the user to enter 10 double numbers. The program should accomplish the follwing:
a. Store the information in a 10-element array.
b. Display the 10 numbers back to the user.
I could do all of the above in main().
Hint: You should use loops, not hardcode the values 0 through 9. It should be easy to convert your program to accept 1000 numbers instead of 10.
For a bonus mark, do at least one of the tasks (a or b) in a separate function. Pass the array to the function; do NOT use global (extern) variables.
I confused above. I wrote a program in the source code. Am I doing wrong? It is below:=
#include<stdio.h>
int main(void)
{
int number[10];
int i;
for (i = 0; i <10; i++)
printf("%d.\n", i, number[i]);
printf("\n\nPress [Enter] to exit program.\n");
fflush(stdin);
getchar();
return 0;
}
Thanks.
Not too bad so far, I'd like to make the following comments:
if you need to input double numbers, you should probably use double rather than int.
you need a statement (maybe in your current loop but possibly in another loop preceding the current one) which inputs the numbers. Look into scanf for this.
Using %d with printf is for integers, not doubles. You will have hopefully already figured out the format string to used when you looked into scanf above.
Bravo for using the correct int main(void) form and for not including conio.h :-)
Once you've figured those bits out, then you can worry about doing it in a separate function.
Based on the code you have given above, I would suggest reading up on the following:
scanf
functions in C, particularly passing arrays to functions: this link should be good.
Note to OP: If you were able to do (a) and (b) in main(), the code above is not complete. It would be nice the functions you created for getting (a) and (b) above done for getting to the root of your "confusion".
Let me know in case you need more help.
HTH,
Sriram
Try this it may sloves your problem.
#include<stdio.h>
int main(void)
{
double number[10];
int i;
printf("Enter double numbers:");
for (i = 0; i <10; i++)
scanf("%lf",&number[i] );
printf("The numbers you entered are:");
for (i = 0; i <10; i++)
printf("%lf\n",number[i] );
return 0;
}