exact multiple scanf input - c

Question

I'm wondering on how to basically input exactly 5 numbers (integers specifically) in one line using simple commands such as while, if and arrays. For example:
if I input 5 numbers separated by spaces,
1 2 3 4 5
program would print
1 2 3 4 5
but, If I input less than 5 or more than 5,
1 2 3 4
program would print
invalid input.
So far I have
#include<stdio.h>
int main(int argc,char *argv[]){
int array[5], numbers;
numbers = 0;
while (numbers < 5) {
scanf("%d", &array[numbers]);
numbers = numbers + 1
}
printf("%d %d %d %d %d\n", array[0], array[1], array[2], array[3], array[4]);
return 0;
}
What about if we assign all the array cell with 9999 (a number not used by the program). And we make a loop to check that each array has been changed to a new value and if its still 9999 it would be invalid. But problem here still lies, how would we just grab one line of different number of input and move on. E.g input 2 3
Output 2 3 9999 9999 9999
Or input 2 3 4
Output 2 3 4 9999 9999

Answer 1

If you want to force the input to be on one line, first read the input and then parse it:
char line[100];
fgets(line, 100, stdin);
char x[100];
int n = sscanf(line, "%d %d %d %d %d %s", array, array+1, array+2, array+3, array+4, x)
if (n != 5)
printf("invalid input\n");
else
printf("read 5 numbers\n");
The x is added to detect if too much was read.

Answer 2

EDIT
To enter 5 numbers you may use
int a[5];
char x;
scanf("%d %d %d %d %d", &a[0], &a[1], &a[2], &a[3], &a[4]);
while(scanf("%*[^\n]%*c")) {
scanf("%c", &x); // after 5 ints were loaded, get rid of rest of the elements untill new line symbol
}
printf("%d %d %d %d %d\n\n", a[0], a[1], a[2], a[3], a[4]);
It will ignore everything after 5 numbers (in fact, it will write to x untill new line symbol appears), but there is no way to easily set number of numbers to read in this case.
You just have to note it will not work if you have less than 5 ints in line.

Answer 3

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int intRead(int array[], int size){
char buff[128];
int status=!0;//status == 0, Something happened!
printf("\ninput %d integer:", size);
while(fgets(buff, sizeof(buff), stdin)){
int count=0;
char*p;
for(p=buff;NULL!=(p=strtok(p, " \t\n"));p=NULL){
char *ck;
int i;
i=(int)strtol(p, &ck, 0);
if(*ck){
fprintf(stderr, "invalid input:can't parse of int <<%s>>\n", p);
status=0;
continue;
}
if(count < size){
array[count++]=i;
continue;
}
count = size + 1;//more than
break;
}
if(count < size)
fprintf(stderr, "invalid input: less than %d\n", size);
else if(count == size) return status;
if(count > size)
fprintf(stderr, "invalid input: more than %d\n", size);
printf("\ninput %d integer:", size);
status = !0;
}
return 0;
}
int main(int argc,char *argv[]){
int array[5];
intRead(array, 5);//or: while(!intRead(array, 5));
printf("%d %d %d %d %d\n", array[0], array[1], array[2], array[3], array[4]);
return 0;
}