How i can remove the last comma from the output? in c-CodePudding

#include<stdio.h>   
#include<unistd.h>

void ft_putchar(char x, char y, char z){
    write(1, &x, 1);
    write(1, &y, 1);
    write(1, &z, 1);
}
void ft_print_comb()
{
    char i, j, k;
    i = '0';
while (i <= '7') {
    j = i   1;
    while (j <= '8') {
        k = j   1;
        while (k <= '9') {
            if(i =='7' && j=='8') */ i created this section to remove comma*/
            {
                ft_putchar('7', '8', '9');
                write(1, '1 ', 1);
            }
            else
                ft_putchar(i, j, k);
                write(1, ", ", 2);
                k  ;
        }
        j  ;
    }
    i  ;
}
}
int main(){
    ft_print_comb();
    return 0;
}

i wrote a code for creating a function that displays all different combinations of three different digits in ascending order, listed by ascending order but i don't know how to remove the last comma from the output? end of my output looks like this

579, 589, 678, 679, 689, 789,

CodePudding user response：

The simplest way to do this is to always print the comma first, but not on the first iteration.

int first = 1;
while (i <= '7') {
    j = i   1;
    while (j <= '8') {
        k = j   1;
        while (k <= '9') {
            if (!first) {
                write(1, ", ", 2);
            } else {
                first=0;
            }
            ft_putchar(i, j, k);
            ...

CodePudding user response：

You can write the comma and space before each number except the first. A boolean flag can be used to indicate whether it is the first output.

#include <stdbool.h>
// ...
bool first = true;
while (i <= '7') {
    j = i   1;
    while (j <= '8') {
        k = j   1;
        while (k <= '9') {
            if (first) first = false;
            else write(1, ", ", 2);
            ft_putchar(i, j, k);
            k  ;
        }
        j  ;
    }
    i  ;
}