#include <stdio.h>
int pick,i,a,b,j;
int q[100];
double tmp;
double m[50][50];
double z[100];
int n[5][5]=
{
    {1,2,3,4,5},
    {5,6,7,8,9},
    {9,10,11,12,13},
    {13,14,15,16,17},
    {17,18,19,20,21}
};
int main ()
{
    printf("Press 1 if you want to enter your own matrix..\n");
    printf("Press 2 if you want to use a predetermined matrix..\n");
    scanf("%d",&pick);
    if(pick==1)
    {
        printf("How many rows do you want in your matrix? ");
        scanf("%d\n",&a);
        printf("How many columns do you want in your matrix? ");
        scanf("%d\n",&b);
        printf("Enter the elements of your matrix row by row..");
        for(i=0;i<a;i++)
        {
            for(j=0;j<b;j++)
            {
                printf("Enter element [%d][%d] ",i,j);
                scanf("%d",m[i][j]);
            }
        printf("\n");
        }


        for(i=0;i<a;i++)
        {
            for(j=0;j<b;j++)
            {
                printf("%d",m[i][j]);
            }
        printf("\n");
        }
    }
    else if(pick==2)
    {
        printf("The predetermined matrix is..\n");
        for(i=0;i<5;i++)
        {
            for(j=0;j<5;j++)
            {
                printf("[%d]",n[i][j]);
            }
            printf("\n");
        }
        printf("Press 1 for the average.. Press 2 for the standard deviation ");
        scanf("%d",&pick);
        if(pick==1)
        {
            printf("Press 1 to choose the average per row.. Press 2 for per column ");
            scanf("%d",&pick);
            if(pick==1)
            {
                printf("This matrix has 5 rows, which do you want to print? ");
                scanf("%d",&pick);
                tmp=0;
                for(i=0;i<5;i++)
                {
                    tmp=tmp+n[pick-1][i];
                }
                tmp=tmp*0.2;
                printf("%d is the average of row %d",tmp,pick);
            }
            else if(pick==2)
            {
                printf("This matrix has 5 columns, which do you want to print? ");
                scanf("%d",&pick);
                tmp=0;
                for(i=0;i<5;i++)
                {
                    tmp=tmp+n[i][pick-1];
                }
                tmp=tmp*0.2;
                printf("%d is the average of column %d",tmp,pick);
            }
        }
        else if(pick==2)
        printf("Press 1 for the standard devation per row.. Press 2 per column ");
        scanf("%d",pick);
        if(pick==1)
        {
            printf("This matrix has 5 rows, which do you want to print? ");
            scanf("%d",&pick);
            tmp=0;
            for(i=0;i<5;i++)
            {
                tmp=tmp+n[pick-1][i];
                z[i]=n[pick-1][i];
            }
            tmp=tmp*0.2;
            for(i=0;i<5;i++)
            {
                z[i]=z[i]-tmp;
                q[i]=z[i]*z[i];
            }
            tmp=0;
            for(i=0;i<5;i++)
            {
                tmp=tmp+q[i];
            }
            tmp=pow(tmp,0.5);
            printf("The standard deviation of the %d row is %d",pick,tmp);
        }
    }
}