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See more:
```#include <stdio.h>
int p,q,x,y,i,j;
int a[100][100],b[100][100],c[100][100];
for(j=0;j<x;j++)
{
for(i=0;i<y;i++)
{
c[j][i]=a[j][i]+b[j][i];
}
}
for(j=0;j<x;j++)
{
for(i=0;i<y;i++)
{
printf(" %d ",c[j][i]);
}
printf("\n");
}
}
int main()
{
int p,q,x,y,i,j;
printf("Enter The Rows Number Of 1st Matrix: ");
scanf("%d",&p);
printf("Enter The Columns Number Of 1st Matrix: ");
scanf("%d",&q);
printf("Enter The Rows Number Of 2nd Matrix: ");
scanf("%d",&x);
printf("Enter The Columns Number Of 2nd Matrix: ");
scanf("%d",&y);
int a[100][100],b[100][100],c[100][100];
for(j=0;j<p;j++)
{
for(i=0;i<q;i++)
{
printf("Enter a%d%d ",j+1,i+1);
scanf("%d",&a[j][i]);
}
}
for(j=0;j<x;j++)
{
for(i=0;i<y;i++)
{
printf("Enter b%d%d ",j+1,i+1);
scanf("%d",&b[j][i]);
}
}
return 0;
}```

The reason I want the code in function cause I want to build a matrix calculator

What I have tried:

I have tried substituting variables while declaring the length of the arrays.
Posted
Updated 28-Jun-22 8:33am
jeron1 28-Jun-22 14:00pm

int p,q,x,y,i,j;

but never initialize them, therefore your for loops will run an unknown number of times.
Rick York 28-Jun-22 16:43pm
They are all acquired via scanf.
jeron1 28-Jun-22 17:55pm
They are local to the Add() function with no scanf, as are the arrays.

## Solution 2

First of all, you can't add 2 matrices of different size.
I would try this change:
C++
```#include <stdio.h>
// This make the matrices and sizes global.
int p,q,x,y;
int a[100][100],b[100][100],c[100][100];
int p,q,x,y,i,j;
int a[100][100],b[100][100],c[100][100];
for(j=0;j<x;j++)
{
for(i=0;i<y;i++)
{
c[j][i]=a[j][i]+b[j][i];
}
}
for(j=0;j<x;j++)
{
for(i=0;i<y;i++)
{
printf(" %d ",c[j][i]);
}
printf("\n");
}
}
int main()
{
int p,q,x,y,i,j;
printf("Enter The Rows Number Of 1st Matrix: ");
scanf("%d",&p);
printf("Enter The Columns Number Of 1st Matrix: ");
scanf("%d",&q);
printf("Enter The Rows Number Of 2nd Matrix: ");
scanf("%d",&x);
printf("Enter The Columns Number Of 2nd Matrix: ");
scanf("%d",&y);
int a[100][100],b[100][100],c[100][100];
for(j=0;j<p;j++)
{
for(i=0;i<q;i++)
{
printf("Enter a%d%d ",j+1,i+1);
scanf("%d",&a[j][i]);
}
}
for(j=0;j<x;j++)
{
for(i=0;i<y;i++)
{
printf("Enter b%d%d ",j+1,i+1);
scanf("%d",&b[j][i]);
}
}
return 0;
}```

Your code do not behave the way you expect, or you don't understand why !

There is an almost universal solution: Run your code on debugger step by step, inspect variables.
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't know what your code is supposed to do, it don't find bugs, it just help you to by showing you what is going on. When the code don't do what is expected, you are close to a bug.
To see what your code is doing: Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.

Debugger - Wikipedia, the free encyclopedia[^]

Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]
Basic Debugging with Visual Studio 2010 - YouTube[^]

1.11 — Debugging your program (stepping and breakpoints) | Learn C++[^]

The debugger is here to only show you what your code is doing and your task is to compare with what it should do.

UPPALAPATI DATTA (RA2111030010270) 29-Jun-22 5:05am
Thanks for a great explanation man🤝

## Solution 1

Refer below Code

```#include <stdio.h>
int main()
{
int r, c, i, j, a[100][100], b[100][100], sum[100][100];
printf("Enter the number of rows (between 1 and 100): ");
scanf("%d", &r);
printf("Enter the number of columns (between 1 and 100): ");
scanf("%d", &c);

printf("\nEnter elements of 1st matrix:\n");
for (i = 0; i < r; ++i)
{
for (j = 0; j < c; ++j)
{
printf("Enter element a%d%d: ", i + 1, j + 1);
scanf("%d", &a[i][j]);
}
}

printf("Enter elements of 2nd matrix:\n");
for (i = 0; i < r; ++i)
{
for (j = 0; j < c; ++j)
{
printf("Enter element b%d%d: ", i + 1, j + 1);
scanf("%d", &b[i][j]);
}
}

// adding two matrices
for (i = 0; i < r; ++i)
{
for (j = 0; j < c; ++j)
{
sum[i][j] = a[i][j] + b[i][j];
}
}

// printing the result
printf("\nSum of two matrices: \n");
for (i = 0; i < r; ++i)
{
for (j = 0; j < c; ++j)
{
printf("%d   ", sum[i][j]);
if (j == c - 1)
{
printf("\n\n");
}
}
}

return 0;
}```

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