Hi everyone. I wrote the following code:
if the number entered is even ie if n=6 , the column of # should be at the 3rd column (ie 6/2)
if the number is odd ie if the number is 9, then the column of # should be at the 5th column

This the code I have to far: However, it prints the column of # always on the first column, so not in the middle as needed. Any help would be greatly appreciated! Thanks.

    #include <stdio.h>

    int main(int argc,char *argv[]) {

        char letterI[100][100];
        int n;
        int retVal;
        int i=0;
        int j=0;
        int middleI;

        printf("Enter a number: ");
        retVal = scanf("%d", &n);

        if (retVal == 1) {
            for (j=0; j<n-1; j++) {
                letterI[0][j] = '#';
                printf("%c", letterI[0][j]);
            }



            if (n%2!=0) {
                for (i=0; i<n-1; i++) {
                    middleI = n/2 + 1;
                    letterI[middleI][i] = '#';
                    printf("%c\n", letterI[middleI][i]);
                }
            }

            else if (n%2==0) {
                for (i=0; i<n-1; i++) {
                    middleI = n/2 - 1;
                    letterI[middleI][i] = '#';
                    printf("%c\n", letterI[middleI][i]);
                }
            }

            for (j=0; j<n; j++) {
                letterI[n-1][j] = '#';
                printf("%c", letterI[n-1][j]);
            }

            printf("\n");

        } else {
            printf("error");
        }

        return 0;
    }

int argc,char *argv[]

1st of all, why do you use that? I don't see in your program nothing related to that.
2nd: this is an example of how you should do it, if I understood corectly.
Here I'm not using any char 2x2 array, but I do simulate one. So, I think this should help you figure out the problem.

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

int even(int x){
    if ((x&1)==0) return (1);
    return (0);
}

int lenght(int x){
    if ((x/10)==0) return (1);
    else return (-1);
}

int main(){
    int i, j, value, nr;
    printf("Insert a nr. (0-9): ");
    scanf("%d", &nr);
    if (even(nr) && lenght(nr)==1){
        value=nr/2;
        printf("\n0123456789\n");
        for (i=0;i<10;i++)
            for (j=0;j<10;j++){
                if (j==value)
                    printf("%c", '#');
                else printf("%c", 'x');
                if (j>8) printf("\n");
            }
    }
    else if (!even(nr) && lenght(nr)==1){
        printf("\n0123456789\n");
        for (i=0;i<10;i++)
            for (j=0;j<10;j++){
                if (j==5) printf ("%c", '#');
                else printf("%c", 'x');
                if (j>8) printf("\n");
            }
    }
    else printf("The number is too big: 0-9 only.");
    return (0);
}

My output:

Insert a nr. (0-9): 2
0123456789
x#xxxxxxxx
x#xxxxxxxx
x#xxxxxxxx
x#xxxxxxxx
x#xxxxxxxx
x#xxxxxxxx
x#xxxxxxxx
x#xxxxxxxx
x#xxxxxxxx
x#xxxxxxxx

for even numbers and for odd:

Insert a nr. (0-9): 9
0123456789
xxxxx#xxxx
xxxxx#xxxx
xxxxx#xxxx
xxxxx#xxxx
xxxxx#xxxx
xxxxx#xxxx
xxxxx#xxxx
xxxxx#xxxx
xxxxx#xxxx
xxxxx#xxxx

Thank you, thank you so much!

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.