C programming : functions with arrays - c

Question

I'm trying to write a function which finds the largest value in a 2d array with row of 4 and col of 4 where the 2d array is filled with user input. I know my main error is with the array in the function but am not sure what it is.
It would be greatly appreciated if someone could find where I went wrong rather than writing a new code. Unless I just went south.
My attempt:
#include <stdio.h>
void largest(int array);
int main() {
int x,y,trash;
int array[4][4];
int row = 4;
int col = 4;
int bigNum,greater;
bigNum=largest(array);
printf("Please enter a value: ")
for(x=0;x<row;x++) {
for(y=0;y<(col);y++) {
scanf("%d",&array[x][y]);
scanf("%d",&trash);
}
}
printf("The largest number in the array is : ",bigNum);
}
void largest(int array[][]) {
for(x=0; x<row; x++) {
for(y=0; y<(col-1); y++) {
if (array[x][y] > array[x][y+1]) {
array[x][y+1] = array[x][y];
}
}
printf("\n")
}
big = array[x][y];
return big;
}

Answer 1

There are a few problems to address here, the first is you can't have int array[][] as a parameter, you need to provide all but the first dimension, int array[][4] would suffice in this limited case.
However, since row and col are local variables in main they aren't visible to your largest functions body, so they'll need to be passed, make the signature
void largest(int row, int col, int array[row][col]);
Since this is a void function, it can't return any value. It will modify the array it's given in place though, so the changes will be visible.
If you're looking for the straight-up log error, the function to find the largest is pretty crazy. A saner implementation would be to just track the largest element you've seen so far:
int largest(int row, in col, int array[row][col]) {
int big = array[0][0]; // assume the first element is the largest
for (int i = 0; i < row, ++i) {
for (int j = 0; j < col; ++j) {
if (array[i][j] > big) big = array[i][j];
}
}
return big;
}
you could then call the function from main as
int bigNum = largest(row, column, array);

Answer 2

You have declared the function largest as void and trying to store the return value of the function, it is not possible, so change it as int data type.
Then the row and the col variable value is not passed to the largest function.
either you should declare it globally or pass it as a argument to the largest function.
And you are trying to get the value for trash, I don't know what is the need for that. you can remove it.
And do the following changes in the largest function:
#include <stdio.h>
int largest(int [4][4]);
int row = 4;
int col = 4;
int main()
{ int x,y,trash;
int array[4][4];
int bigNum,greater;
printf("Please enter a value: ");
for(x=0;x<row;x++)
{
for(y=0;y<col;y++)
{
scanf("%d",&array[x][y]);
//scanf("%d",&trash);
}
}
bigNum=largest(array);
printf("The largest number in the array is : %d\n",bigNum);
return 0;
}
int largest(int array[4][4])
{
int x=0,y=0,big=array[0][0];
for(x=0;x<row;x++)
{
for(y=0;y<col;y++)
{
if (array[x][y]>big)
{
big = array[x][y];
}
}
printf("\n");
}
return big;
}
Try this code!!!!!

Answer 3

You need to get the values in the array from the user first. So you main should be:
int main()
{ int x,y,trash;
int array[4][4];
int row = 4;
int col = 4;
int bigNum,greater;
printf("Please enter a value: ")
for(x=0;x<row;x++)
{
for(y=0;y<(col);y++)
{
scanf("%d",&array[x][y]);
scanf("%d",&trash);
}
}
bigNum=largest(array);
printf("The largest number in the array is : ",bigNum);
return 0; //Because it is "int" main and not "void" main
}

Answer 4

Array is not initialized and you are doing this
bigNum=largest(array);
You should be finding the largest when you have elements in your array.
There are many other bugs in this code:
The largest function is not proper and it is returning void
You can't have array[][] as your parameter and it should be array[][4].
OMG when I went through the code I found that there is bug in almost each and every line.
#include <stdio.h>
int largest(int array[][4]);
int main()
{ int x,y;
int array[4][4];
int row = 4;
int col = 4;
int bigNum;
printf("Please enter a value: ");
for(x=0;x<row;x++)
{
for(y=0;y<(col);y++)
{
scanf("%d",&array[x][y]);
}
}
bigNum=largest(array);
printf("The largest number in the array is : %d",bigNum);
}
int largest(int array[][4])
{
int max=0;
int x,y;
max = array[0][0];
for(x=0;x<4;x++)
{
for(y=0;y<4;y++)
{
if (array[x][y]>max)
{
max = array[x][y];
}
}
}
return max;
}

Answer 5

Errors in your code
You cannot pass two dimensional arrays like you are doing.
Your logic to find the largest is not proper, you are comparing at any movement two adjacent elements and if the first is small you are actually making them equal
Variable scoping errors, row, col, x and y are bound to main method and you cannot access them in other method. look at Global Variables to access them anywhere you want within the program file.
Unnecessary scanf for trash and printf in largest method.
#include<stdio.h>
int row = 4;
int col = 4;
int largestElement(int array[][4],int row);
int main()
{
int x,y;
int array[row][col];
int bigNum,greater;
printf("Please enter a value: ");
for(x=0;x< row;x++)
{
for(y=0;y< col;y++)
{
scanf("%d",&array[x][y]);
}
}
bigNum = largestElement(array, sizeof(array) / sizeof(array[0]));
printf("The largest number in the array is : ",bigNum);
}
int largestElement(int array[][4],int row)
{
int x,y;
int big =0;
for(x=0;x<row;x++)
{
for(y=0;y<(col-1);y++)
if (big < array[x][y]) big = array[x][y];
}
return big;
}

Answer 6

You try this code for finding the biggest elements in the Two dimensional array.
#include <stdio.h>
int largest(int [][4],int ,int);
int main() {
int x,y,trash;
int array[4][4];
int row = 4;
int col = 4;
int bigNum,greater;
printf("Please enter a value: ");
for(x=0;x<row;x++) {
for(y=0;y<col;y++) {
scanf("%d",&array[x][y]);
}
}
bigNum=largest(array,row,col);
printf("The largest number in the array is:%d ",bigNum);
return 0;
}
int largest(int array[][4], int row, int col)
{
int x,y,big=array[0][0];
for(x=0; x<row; x++) {
for(y=0; y<col-1; y++) {
if(big<array[x][y])
big=array[x][y];
}
}
return big;
}