everyone!
I create matrix with random elements:
static int array[10][10];
int i, j, m, n, sum = 0;
printf("Enter the order of the matrix\n");
scanf("%d %d", &m, &n);
for (i = 0; i < m; ++i)
{
for (j = 0; j < n; ++j)
{
printf("%d ", rand() % 10);
}
printf("\n");
}
And this is one function to sum row elements:
for (i = 0; i < m; ++i)
{
for (j = 0; j < n; ++j)
{
sum = sum + array[i][j];
}
printf("Sum of the %d row is = %d\n", i, sum);
sum = 0;
}
My problem is that program wont to sum it properly, program just print 0 for result.
Also, when I add manual elements, program works fine, but wont with random numbers.
Someone to help me? Thank you!
You haven't actually assigned the values to the array; you're just printing them.
for (i = 0; i < m; ++i)
{
for (j = 0; j < n; ++j)
{
int num = rand() % 10;
printf("%d ", num);
array[i][j] = num;
}
printf("\n");
}
is probably what you want.
Also the array has space for only 10 x 10 elements. So you need to validate that the inputs for m and n do not exceed that limit.
The default value of int type in C is 0. Because you do not enter the value to array, so all of values of this array are equal to 0. So sum = 0 after all calculations.
Try to initialize values for this array. For example, in the first for loop (the for loop content printf with rand() function):
array[i][j] = rand() % 10;
OR
array[i][j] = 1; // or whatever you want
Related
Im taking a C programming beginning course, and have a problem with a for loop.
I want to make two double arrays. One that takes input from user, and one that sums the inputs.
I then want to output the two arrays. One that shows the input, and one that shows the sums og the input in every cell.
The problem comes when I try to show the sum for every "cell" in the array.
The output just becomes the same as the input.
I can solve it with:
// print all the numbers in the second array
for (i = 0; i < n; i++) {
sum = sum + a[i];
printf("%lf ", sum);
but then the assignment wouldn't be solved. Hope you can educate me.
#include <stdio.h> #include <stdlib.h>
int main(void) {
int n; //numbers of cells
int i; //The numbers in the cells
printf("How many cells in the array would you like? \n");
scanf("%d", &n);
double a[n], sum=0; // declare an array and a loop variable.
double b[n], sumo=0;
printf("Enter the numbers:\n");
for (i = 0; i < n; i++) { // read each number from the user
scanf("%lf", &a[i]);
}
printf("The results, my lord:\n");
// print all the numbers in the first array
for (i = 0; i < n; i++) {
printf("%lf ", a[i]);
}
printf("\n"); //THIS IS WHERE THE PROBLEM STARTS
// print all the numbers in the second array
for (i = 0; i < n; i++) {
b[i] = b[i] + a[i];
printf("%lf ", b[i]);
}
return 0;
}
For starters the array b is not initialized
double b[n], sumo=0;
So this statement
b[i] = b[i] + a[i];
invokes undefined behavior.
It seems what you need is the following for loop
for (i = 0; i < n; i++) {
b[i] = a[i];
if ( i != 0 ) b[i] += a[i-1];
printf("%lf ", b[i]);
}
You can calculate the sum (aka the b array) when you read the user data:
for (i = 0; i < n; i++)
{
scanf("%lf", &a[i]);
if (i == 0)
{
b[i] = a[i];
}
else
{
b[i] = b[i-1] + a[i];
}
}
or do it like:
scanf("%lf", &a[0]);
b[0] = a[0];
for (i = 1; i < n; i++)
{
scanf("%lf", &a[i]);
b[i] = b[i-1] + a[i];
}
or do it like:
sum = 0;
for (i = 0; i < n; i++)
{
scanf("%lf", &a[i]);
sum += a[i];
b[i] = sum;
}
The last part is how I solved the problem. I found the issue that. I didn't update the "sum" for ever loop. It adds a new value in b[I] this way. :-)
double a[n], sum=0; // declare an array and a loop variable.
double b[n];
printf("Enter the numbers:\n");
for (i = 0; i < n; i++) { // read each number from the user
scanf("%lf", &a[i]);
}
printf("The results, my lord:\n");
// print all the numbers in the first array
for (i = 0; i < n; i++) {
printf("%.2lf ", a[i]);
}
printf("\n");
// print all the numbers in the second array
for (i = 0; i < n; i++) {
sum = sum + a[i];
b[i] = sum;
printf("%.2lf ", b[i]);
I have this piece of code that is supposed to sum all the even numbers but it isnt working
int n, k = 0, sum = 0;
for (i = 0; i < n; i++)
if (s[i] % 2 == 0) {
k++;
for (int i = 0; i < n; i++)
sum += s[i];
printf("%i ", s[i]);
}
printf("\n sum of even numbers=%i", sum);
int i, sum = 0;
for (i=0; i < n; i++) //n is the number of elements in the array
{
if (s[i] % 2 == 0)
sum = sum + s[i];
}
printf("Sum of the even numbers = %d",sum);
There was no need for a nested loop. Just delete the inner for
I wrote to program in C to attempt to print array elements in descending order. I wrote a nested loop which would find the maximum element of the array and the value of the element would be set to later 0. This process would be repeated for all the elements. However, in the output, I am getting the first 2-3 values as desired but the remaining values are garbage. Any suggestions?
int main() {
int i, j, n, k;
scanf("%d\n", &n);
int a[100], b[100];
for (i = 0; i < n; i++) {
scanf("%d", &a[i]);
}
for (i = 0; i < n; i++) {
int max = a[i];
for (j = i; j < n; j++) {
if (a[j] > max) {
max = a[j];
b[i] = max;
}
}
for (k = 0; k < n; k++) {
printf("%d", a[k]);
if (a[k] == b[i]) {
a[k] = 0;
}
}
printf("\n");
}
for (i = 0; i < n; i++) {
printf("%d ", b[i]);
}
}
The main issue is that you only set b[i] = max; when you find a new max, but since you initialized max to be a[i] it could happen that it already holds the maximum value. So the if never executes, therefore b[i] is not written and there's garbage value in it. You should move this line from the if after that for loop.
Another issue is that you initialize j with i in this loop. You should initialize it to 0.
The changed part:
for (j = 0; j < n; j++) {
if (a[j] > max) {
max = a[j];
}
}
b[i] = max;
Hi all i have a problem with this exercise in Language C.
The exercise is:
Given a matrix write a function that:
A) Calculate and return the sum of the elements.
B) Calculate and return the average of the i-th line
I did my own procedure but i have a lot errors.
My procedure is:
#include <stdio.h>
#include <stdlib.h>
void main(){
int n=10;
int m=10;
int i;
int j;
int mat [i][j];
int sum=0;
for (i=0;i<n;i++){
for (j=0; j<m;j++)
sum=sum+mat[i][j];}
printf("The sum of all elements of matrix is:%d",sum);
somma=0;
for (j=0;j<m;i++){
sum=sum+mat[i][j];
sum=sum/m
printf("The average of i-th line is:%d",sum);
}
}
i think that i have to put scanf somewhere but i don't know where.
I hope that you can help me
thank you!
You declare a matrix with undefined sizes
int mat [i][j];
where i and j are uninitizlized.
You probably want
int mat [n][m];
Moreover your matrix should be inizialized with values, otherwise you'll get the sum of stack garbage.
At the end, a possible solution is
#include <stdio.h>
int main(void)
{
int n = 2;
int m = 2;
int i;
int j;
int mat[n][m];
int sum = 0;
for (i = 0; i < n; i++)
{
for (j = 0; j < m; j++)
{
printf("Insert value of mat[%d][%d]: ", i, j);
scanf("%d", &mat[i][j]);
}
}
for (i = 0; i < n; i++)
{
for (j = 0; j < m; j++)
{
sum = sum + mat[i][j];
}
}
printf("The sum of all elements of matrix is: %d\n", sum);
for (i = 0; i < n; i++)
{
sum = 0;
for (j = 0; j < m; j++)
{
sum = sum + mat[i][j];
}
sum = sum / m;
printf("The average of line %d is: %d\n", i, sum);
}
}
As you can see I changed the average calculation:
First of all you wrote a j loop incrementing i
You must loop for all lines, so you must add a for loop that inc rows
sum must be reset each time you calculate the row average
take notes that the average is calculated using integers, so no decimals will be available.
I have a program where I enter numbers to make a matrix. Then it sums numbers in each row and prints the sum. But I need to print even the row with the biggest sum. Can someone please help me? Thanks. http://onlinemovies.pw
Here is the code:
#include <stdio.h>
int main (void)
{
static int array [10][10];
int i, j, m, n, sum = 0;
printf ("Enter the order of the matrix\n");
scanf ("%d %d", &m, &n);
printf ("Enter the co-efficients of the matrix \n");
for (i = 0; i < m; ++i)
{
for (j = 0; j < n; ++j)
{
scanf ("%d", &array [i][j]);
}
}
for (i = 0; i < m; ++i)
{
for (j = 0; j < n; ++j)
{
sum = sum + array[i][j] ;
}
printf ("Sum of the %d row is = %d\n", i, sum);
sum = 0;
}
}
You need to declare a variable and intialize it with a minimum value, if those values are always positive you can initialize it to 0:
int max = 0;
if not, you can use INT_MIN defined in <limits.h>
#include <limits.h>
...
int max = INT_MIN;
then use it in your loop:
int max = INT_MIN, imax = 0;
for (i = 0; i < m; ++i)
{
for (j = 0; j < n; ++j)
{
sum = sum + array[i][j] ;
}
printf ("Sum of the %d row is = %d\n", i, sum);
if (sum > max) {
max = sum;
imax = i;
}
sum = 0;
}
printf ("Max row (%d) is = %d\n", imax, max);