Trace of a matrix - C program

/*trace of a matrix*/

#include<stdio.h>

#include<math.h>

void

main()

{

                int i,j,a[20][20];

                float s=0.0;

                printf("enter the elements of input matrix:");

                for(i=0;i<2;i++)

                {

                                for(j=0;j<2;j++)

                                                scanf("%d",&a[i][j]);

                }

                printf("the input matrix is:");

                printf("\n");

                for(i=0;i<2;i++)

                {

                                for(j=0;j<2;j++)

                                                printf("%d\t",a[i][j]);

                                printf("\n");

                }

                for(i=0;i<2;i++)

                {

                                for(j=0;j<2;j++)

                                {

                                                if(i==j)

                                                                s=s+a[i][j];

                                }

                }

                printf("\n the trace is=%f\n",s);

}

RESULT:

enter the elements of input matrix:1 2 3 4

the input matrix is:

1       2

3       4

 the trace is=5.000000

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