I need to determine if a rectangular matrix has two rows of positive elements in C. I write part code for the set matrix and output its elements. I don't know how to check the positive elements in the row. Please help me
#include <stdio.h>
#include <conio.h>
#include <locale.h>
#define M 3
#define N 4
int main() {
setlocale(LC_ALL, "Rus");
float a[M][N]; //set matrix with 3 row and 4 column
int i, j; // row and column index
for (i = 0; i < M; i++) {
for (j = 0; j < N; j++)
scanf_s("%f", &a[i][j]);
}
for (i = 0; i < M; i++) {
printf("%d line:", i + 1);
for (j = 0; j < N; j++)
printf("%f", a[i][j]);
printf("\n");
}
_getch();
return 0;
}
So, I make some changes in my code after reading comments. Thanks a lot. But it's not working.
#include <stdio.h>
#include <conio.h>
#include <locale.h>
#define M 3
#define N 4
int main(){
setlocale(LC_ALL, "Rus");
float a[M][N]; //обьявление матрицы 3 строки и 4 столбца
int i, j; // индексы строки и столбца
int count;
for (i = 0; i < M; i++){
for (j = 0; j < N; j++)
scanf_s("%f", &a[i][j]);
}
for (i = 0; i < M; i++){
printf("%d-я строка:", i + 1);
for (j = 0; j < N; j++)
printf("%f", a[i][j]);
printf("\n");
}
count = 0;
for (i = 0; i < M; i++){
for (j = 0; j < N; j++)
if (a[i][j] > 0){
count++;
printf("%d", count);
}
}
_getch();
return 0;
}
What you need to do is to set a counter to 0 . Every time all the values are positive in row add 1 your counter. You can do that by a loop. If a value of your matrix a[i][j] is less than 0 just continue and move on to then next row.
Related
this code gives a 4x3 array of numbers from 2 to 100:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define LINES 4
#define COLUMNS 3
int main(void) {
int matriz[LINES][COLUMNS];
int i, j;
srand(time(NULL));
for(i = 0; i < LINES; i++){
for(j = 0; j < COLUMNS; j++){
matriz[i][j] = rand() % 99 + 2;
}
}
printf("Matriz[%i][%i]:\n", LINES, COLUMNS);
for(i = 0; i < LINES; i++){
for(j = 0; j < COLUMNS; j++){
printf("\t%i", matriz[i][j]);
}
printf("\n");
}
return 0;
}
what can I do so this array only receive EVEN numbers from the rand function?
I've been trying to sort columns in a matrix (the dimensions are m,n <= 10) via the lexicographical order (if the columns share the same element, then we compare the elements in the row beneath etc.) with some additional conditions. I need to use functions to print the matrix, input random integers up to 5 as its elements and finally arrange the matrix. I think I got the printing and random inputs correctly but I can't figure out the sorting. Plus I can't use global variables which I have no idea how to do, since I haven't been shown. An example matrix would be :
#include <stdio.h>
#include <stdlib.h>
int main()
{
int m, n;
int mat[10][10];
void print_matrix()
{
int i, j;
for (i = 0; i < m; i++)
{
for (j = 0; j < n; j++)
{
printf("%d ", mat[i][j]);
}
printf("\n");
}
}
void random_int()
{
int i, j;
srand((unsigned)time(NULL));
for (i = 0; i < m; i++)
{
for (j = 0; j < n; j++)
{
mat[i][j] = rand() % 5;
}
}
}
void arrange()
{
int i, j, k, a;
for (j = 0; j < n; ++j)
{
for (i = 0; i < m; ++i)
{
for (k = i + 1; k < m; ++k)
{
if (mat[i][j] < mat[k][j])
{
a = mat[i][j];
mat[i][j] = mat[k][j];
mat[k][j] = a;
}
}
}
}
}
printf("Input the number of rows : ");
scanf("%d", &m);
printf("Input the number of columns: ");
scanf("%d", &n);
random_int(mat[m][n]);
print_matrix(mat[m][n]);
arrange(mat[m][n]);
print_matrix(mat[m][n]);
return 0;
}
Try this solution(will work for input 0-8 only), also used global variables:
There have multiple solutions. but is the easiest one.
I have converted each of the columns as an integer value. then bubble sorted the integers. After sorting. I have then converted the integer value to digits. (You have to know how to convert individual digits to multiple digit integer and multiple digit integers to single-digit.
Note I have added one(1) with each digit. Because the input can be zero(0). if you convert 0 0 2 1 to an integer will be only 21. the first two digits lost. So I have added 1. so 0 0 2 1 will be converted to 1132. I have done (added 1) for each input(deducted 1 after sorting). so it will not affect other inputs. Be careful input have to be from(0 to 8)
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int m, n;
int mat[10][10];
int generatedNumber[10];
void print_matrix()
{
printf("The matrix is:\n");
int i, j;
for (i = 0; i < m; i++)
{
for (j = 0; j < n; j++)
{
printf("%d ", mat[i][j]);
}
printf("\n");
}
}
void random_int()
{
int i, j;
srand((unsigned)time(NULL));
for (i = 0; i < m; i++)
{
for (j = 0; j < n; j++)
{
mat[i][j] = rand() % 5;
}
}
}
void arrange()
{
int i, j, k, a;
for (j = 0; j < n; ++j)
{
int number = 0;
for (i = 0; i < m; ++i)
{
number = number * 10 + mat[i][j] + 1;///Adding one for avoiding zero(0)
}
generatedNumber[j] = number;
}
for(i = 0; i < n; i++)
{
for(j = 0; j < n-i-1; j++)
{
if( generatedNumber[j] > generatedNumber[j+1])
{
// swap the elements
int temp = generatedNumber[j];
generatedNumber[j] = generatedNumber[j+1];
generatedNumber[j+1] = temp;
}
}
}
for(i = 0; i < n; i++)///columwise
{
int generatedColumnvalue = generatedNumber[i];
for(j = m -1; j>= 0; j--)///row wise and fro last vaue to first
{
mat[j][i] = (generatedColumnvalue%10)-1;///removing extra added 1
generatedColumnvalue/=10;
}
}
}
int main()
{
printf("Input the number of rows : ");
scanf("%d", &m);
printf("Input the number of columns: ");
scanf("%d", &n);
random_int();
print_matrix();
arrange();
print_matrix();
return 0;
}
Good day to everybody. My task is to determine if a rectangular matrix has two rows of positive elements. I write the code below. At end I try to chect statement about positive row, but it's not working at all. Please explain me how to correct get the access to the each row and column in matrix, and meaybe edit my code.
#include <stdio.h>
#include <conio.h>
#include <locale.h>
#define M 3
#define N 4
int main(){
setlocale(LC_ALL, "Rus");
float a[M][N]; //set matrix with 3 row and 4 column
int i, j; // row and column index
int count;
for (i = 0; i < M; i++){
for (j = 0; j < N; j++)
scanf_s("%f", &a[i][j]);
}
for (i = 0; i < M; i++){
printf("%d-я строка:", i + 1);
for (j = 0; j < N; j++)
printf("%f", a[i][j]);
printf("\n");
}
count = 0;
for (i = 0; i < M; i++){
for (j = 0; j < N; j++)
if (a[i][j] > 0){
count++;
printf("%d", count);
}
}
_getch();
return 0;
}
When counting the number of positive elements in a row, you need to set the count back to zero for each row.
So instead of:
count = 0;
for (i = 0; i < M; i++){
for (j = 0; j < N; j++)
if (a[i][j] > 0){
count++;
printf("%d", count);
}
}
you need
for (i = 0; i < M; i++){
count = 0;
for (j = 0; j < N; j++) {
if (a[i][j] > 0){
count++;
}
}
printf("row %d has %d positive elements\n", i, count);
}
I have a 2d array filled with 0's and i'm trying to fill the main diagonal with numbers from 1 to n, this is the main code:
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main()
{
srand(time(NULL));
int m, n, i, j;
printf("Number of rows and columns:");
scanf("%d", &n);
int a[n][n];
for (i = 0; i < n; i++)
for(j = 0; j < n; j++)
a[i][j] = rand() % 1;
printf("The matrix is:\n");
for (i = 0; i < n; i++)
{
printf(" \n ");
for(j = 0; j < n; j++)
{
printf(" %d\t ", a[i][j]);
}
}
}
What I've tried to do is to fill the diagonal manually, but that's not what I want to do. I want to make it fill itself automatically. I need to do it without using any functions.
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
arr[i][j] = ((i == j) * (i + 1));
}
}
The simplest way is to add this part after you fill the matrix with zeros.
for (i = 0; i < n; i++)
arr[i][i] = i + 1;
I am trying to create a program which prints a matrix of integers, but the output returns weird numbers before the actual matrix. There are no compiling errors.
This is what my code looks like: //ignore void function for now, focus on main function::
#include <stdio.h>
#include <stdlib.h>
//array[30][30] = 2D array of max 30 rows and 30 columns
//n = number of rows and columns
void printmatrix(int array[30][30], int n){
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
printf("%d", array[i][j]);
}
printf("\n");
}
return;
}
int main(){
int n;
scanf("%d", &n);
int ints2D[n][n];
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
scanf("%d", &ints2D[i][j]);
}
}
printmatrix(ints2D, n);
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
printf("%d ", ints2D[i][j]);
}
printf("\n");
}
return 0;
}
And this is my output (I only want the last three lines)
123
-514159984327663
-51415932632766-514159305
1 2 3
4 5 6
7 8 9
You are missing a space in "%d" in printmatrix, and, more importantly, it is not proper to pass an int [n][n] array for an int [30][30] parameter unless n is 30.
Change void printmatrix(int array[30][30], int n) to void printmatrix(int n, int array[n][n]), and change printmatrix(ints2D, n); to printmatrix(n, ints2D);. That makes the type of the argument you are passing match the type of the parameter.
In your function args you defined the array as fixed size ([30][30]) but you are passing a VLA ([3][3] in your example) which makes it find uninitialized memory and why you are seeing the strange numbers.
#Eric Postpischil answer is spot on. Another way to solve it: 2d arrays could be flatten into 1d. Here is a working code for you:
#include <stdio.h>
#include <stdlib.h>
//array[30][30] = 2D array of max 30 rows and 30 columns
//n = number of rows and columns
void printmatrix(int *array, int n){
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
printf("%d ", array[i * n + j]);
}
printf("\n");
}
return;
}
int main(){
int n;
scanf("%d", &n);
int ints2D[n * n];
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
scanf("%d", &ints2D[i * n + j]);
}
}
printmatrix(ints2D, n);
for(int i = 0; i < n; i++){
for(int j = 0; j < n; j++){
printf("%d ", ints2D[i * n + j]);
}
printf("\n");
}
return 0;
}