How do I use scanf() to take an arbitrary amount of integers?

Question

The program takes an arbitrary amount of integers as an input and gives an output of that integer and that amount of stars.

E.g.

In: 1 2 3
Out: 
1 | *
2 | **
3 | ***

Another example:

In: 2 5 6 8
Out:
2 | **
5 | *****
6 | ******
8 | ********

How do I do it??

Btw, amateur C programmer

And how do I add a single line space "\n" between lines in Stack Overflow question format

You should look at http://stackoverflow.com/questions/3764014/how-do-you-read-scanf-until-eof-in-c (reading until End Of File) — irrelephant, Aug 07 '12 at 05:27
if you want to be a great programmer you have to read books and use search! — Dmitry Zagorulkin, Aug 07 '12 at 05:29
Read the input, tokenize it, parse it, and print. It should be possible with `fgets` and `strtoul`. — Kerrek SB, Aug 07 '12 at 05:30

score 4 · Answer 1 · edited Aug 07 '12 at 05:44

4

for reading numbers from a line, you can :

#include <stdio.h>

int main(){
    char buffer[1000];
    if (fgets(buffer, sizeof(buffer), stdin) != 0){
        int i,j,a;
        for(i=0; sscanf(buffer+i,"%d%n",&a,&j)!=EOF; i+=j){
            while(a-->0){
                printf("*");
            }
            printf("\n");
        }
    }
    return 0;
}

edited Aug 07 '12 at 05:44

Jonathan Leffler

730,956
141
904
1,278

answered Aug 07 '12 at 05:34

lavin

2,276
2
13
15

3

Never use `gets()`; it's inherently unsafe and has been removed from the language. – Keith Thompson Aug 07 '12 at 05:36
oops...now changed to fgets.. XD ... my apology – lavin Aug 07 '12 at 05:38
1

+1 for the proper use of the `-->` operator. – Philip Aug 07 '12 at 06:16

score 0 · Answer 2 · answered Aug 07 '12 at 05:35

It's better to have a loop for this manner.
While user has not entered "\n" your program should be able to consider them as integers. Of course you can add some other checks as well.

Something like this:

int number = 0;
char c = '';
while(c != '\n'){
    getch(c);
    scanf("%d", &number);
    /*Do your star thing or add this number to an array for the later consideration*/
}

This is not fully tested and you might have to have some changes.

score 0 · Answer 3 · answered Aug 09 '12 at 12:41

#include <stdio.h>

#define SIZE 8

int input_numbers(int numbers[]){
    int i=0,read_count;
    char ch;

    printf("In: ");
    while(EOF!=(read_count=scanf("%d%c", &numbers[i], &ch))){
        if(read_count==2)
            ++i;
        if(i==SIZE){
            fprintf(stderr, "Numeric number has reached the Max load.\n");
            return i;
        }
        if(ch == '\n')
            break;
    }
    return i;
}

void output_numbers(int numbers[], int size){
    int i,j;
    printf("Out:\n");
    for(i=0;i<size;++i){
        printf("%d | ", numbers[i]);
        for(j=0;j<numbers[i];++j){
            printf("*");
        }
        printf("\n");
    }
}

int main(void){
    int numbers[SIZE];
    int n;

    n=input_numbers(numbers);
    output_numbers(numbers, n);
    return 0;
}

How do I use scanf() to take an arbitrary amount of integers?

3 Answers3

Linked