CODEWITHSUNDEEP
ccrashruntime-error
Ambidextrous
Ambidextrous

Reputation: 872

Why does this program crashes on execution?

I am trying to run this code on Dev C++ but it keeps on crashing after the user inputs the two numbers. The program takes input m and n from user two numbers and then returns the output as the solution of the function A which is:

A(m,n) = A(m,n-1)+ A(m-1, n) , if m,n >0

A(m,n) = m-n if m or n <0

Can anybody please tell me why is it happening?

#include<stdio.h>
#include<stdlib.h>

int main() {
    int num1=0;
    int num2=0;
    int rows=0;
    int columns=0;
    int i,j,**array;
    printf("Enter two non-negative integer numbers \n");
    scanf("%d %d",&num1,&num2);  

    //create 2d-Array

    rows=num1+1;
    columns=num2+1;
    array=malloc(rows * sizeof(int *));

    for(i=0;i<rows;i++)
    {
       array[i]=malloc(columns*sizeof(int));    
    }

    //Fill data in array

    computeArray(array,rows,columns);


    // Display contents of array

    for (i = 0; i < rows; i++ )
    {
      for(j= 0; j < columns; j++ )
      {
         printf("array[%d][%d] = %d\n", i,j, array[i][j] );
      }
    }    

    getch();
    return 0; 
}

int computeArray (int **array, int rows, int columns) {
    int i,j;
    for(i=0; i<rows;i++)
    {
            for(j=0;j<columns;j++)
            {
                 array[i][j]=computeFunction(array,i,j);
            }
    }        
    return **array; 
}

int computeFunction(int **array, int i, int j) {
    int value=0;
    if((i<0)||(j <0))
    {
        value = i-j; 
        printf("%d",value);
        return value;                 
    }
    else 
    {
        value = (array[i][j-1] + array[i-1][j]);
        printf("%d",value);
        return value;
    }
    return value; 
}

Crash Screenshot

Upvotes: 0

Views: 334

Answers (2)

haccks
haccks

Reputation: 106002

When program's behavior is undefined, anything could happen. You should declare a prototype for the function computeArray and computeFunction before main: 

int computeArray (int **array, int rows, int columns);
int computeFunction(int **array, int i, int j);

and change 

if((i<0)||(j <0)) {...}

in computeFunction to 

if((i<=0) || (j <= 0)){...}

Upvotes: 1

Jakub
Jakub

Reputation: 573

&& instead of || may help. The code fails at the 

value = (array[i][j-1] + array[i-1][j]);

line, when j==0.

Debuggers tend to be very useful for spotting simple mistakes. Use them.

Upvotes: 1

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