How can i run a command only one time inside of for loop?-CodePudding

How can i run a command only one time inside of for loop? I couldn't find how to do it so i wrote code like that. But the problem on this code you can see when the program goes to else command it doesn't work.

I just wanted to see odd and even numbers with using for loop but i don't want to get result like; Even numbers :12 Even numbers :28 Even numbers :46

I just want to see only one time print Even numbers and then print numbers like; Even numbers: 12 28 46 e.t.c

I hope i could explain clear. Waiting for your help. Thanks.

My alternative but wrong code is;

#include <stdio.h>

int main()
{   
    int num [] = {12, 14, 16, 33, 65, 98, 45, 25, 87, 18, 20};
    
    printf("even numbers:");
    printf("\t\t\t\t Odd numbers:");

    for (int i = 0; i < 11; i  ) {
        if (num[i] % 2 == 0) {
            printf("\n%d", num[i]);
        }
        else {
            printf("\t\t\n%d");
        }   
    }
        
    return 0;
}

CodePudding user response：

You want two loops:

#include <stdio.h>

int main(void)
{
    int num[] = {12,14,16,33,65,98,45,25,87,18,20};
    size_t n = sizeof num / sizeof *num;

    printf ("Even numbers:\t\t\t\tOdd numbers:\n");

    for (size_t i = 0; i < n; i  ) {
        if (num[i] % 2 == 0) {
            printf ("%d ", num[i]);
        }
    }
    printf("\r\t\t\t\t\t");
    for (size_t i = 0; i < n; i  ) {
        if (num[i] % 2 != 0) {
            printf ("%d ", num[i]);
        }
    }
    printf("\n");
    return 0;
}

Output:

Even numbers:               Odd numbers:
12 14 16 98 18 20           33 65 45 25 87

Notice the \r to go to the beginning of the line

CodePudding user response：

Here a different format:

#include <stdio.h>

int main(void) {
    unsigned num []={12,14,16,33,65,98,45,25,87,18,20};
    printf("even numbers"
        "\todd numbers\n");
    const char *prefix[] = {"", "\t\t"};
    for(unsigned i = 0; i < sizeof(num) / sizeof(*num); i  ) {
        printf("%s%u\n", prefix[num[i] % 2], num[i]);
    }
}

and the output is:

even numbers    odd numbers
12
14
16
                33
                65
98
                45
                25
                87
18
20

CodePudding user response：

You just want evens on one line, and odds on the next, right?

"Factoring out" common processing into a function is always a good idea.

#include <stdio.h>

void show( int num[], int nItems, char *title, int rem ) {
    printf( title );
    for( int i = 0; i < nItems; i   )
        if( num[i]%2 == rem )
            printf( "%d ", num[ i ] );
    printf( "\n" );
}

int main () {
    int num [] = { 12, 14, 16, 33, 65, 98, 45, 25, 87, 18, 20 };

    show( num, sizeof num/sizeof num[0], "even numbers: ", 0 );
    show( num, sizeof num/sizeof num[0], "odd numbers: ", 1 );

    return 0;
}

Output:
even numbers: 12 14 16 98 18 20
odd numbers: 33 65 45 25 87