how to get multiple number from one line in C?

Question

If I want to get input 3 numbers, I can write code like this:

scanf("%d %d %d", &a, &b, &c);

but how can I dynamically get the number of inputs from one line?

For example, if user enters N(number), then I have to get N integer number inputs from one line like above.

The input and output should be :

how many do you want to enter: 5
1 2 3 4 5
sum: 15

Read one value at a time in a loop until input is exhausted. — William Pursell, May 03 '17 at 14:44
http://stackoverflow.com/questions/15291523/accepting-any-number-of-inputs-from-scanf-function — Peter Chaula, May 03 '17 at 14:47
{%d} is possible to read as a string, the variable arguments are not string — user7159879, May 03 '17 at 14:47
Note that `scanf()` won't care if the three values are all on one line or on three separate lines, or if there's a thousand blank lines between each number. If you want line-based input, don't use `scanf()`; it doesn't care about lines. — Jonathan Leffler, May 03 '17 at 14:52

score 5 · Accepted Answer · answered May 03 '17 at 14:51

5

Since scanf returns the amount of variables filled you can loop until scanf has no more value to read or the count is matched:

int count = 0;
printf("how many do you want to enter: ");
scanf("%d", &count);
int val = 0;
int sum = 0;
int i = 0;
while(scanf("%d ", &val) == 1 && i++ < count)
  sum += val;

answered May 03 '17 at 14:51

Hatted Rooster

35,759
6
62
122

If I enter 1 2 3 4 5, these numbers are in standard input buffer. so, does scanf read input from this buffer although I just enter one line?? That's why these instructions works?? – user7159879 May 03 '17 at 15:37

Rajeev Singh · Answer 2 · 2017-05-03T15:13:41.167

As you don't know the size of inputs previously it's better to create a dynamic array based on the input size provided by the user. Input the size of the array and create an array of that size. Then you can easily loop through the array and do whatever you want with it.

int count = 0, sum = 0;
printf("how many do you want to enter: ");
scanf("%d", &count);

int *num = malloc(sizeof(int)*count);

for(int i = 0; i < count; i++) {
    scanf("%d ", &num[i]);
    //sum += num[i];
}

how to get multiple number from one line in C?

2 Answers2