Read in space delimited numbers using scanf and storing them in an array - C

The "%d" consumes leading white-space such as ' ' and '\n', not just ' '.

So when the user enters "123 456 789" Enter, scanf() is called again waiting for more input. It will continue to wait until non-numeric data in entered, stdin is closed or rarely experiences an IO error.

Since stdin is usually buffered, stdin and scanf() do not see any input from a line until the Enter is pressed.

while (scanf("%d", &sourceArr[i++]) == 1); 

If code needs to to end input with Enter, use fgets() to read a line. Then parse it using sscanf() or strtol(). The below uses "%n" to record the number of char scanned.

char buf[100]; printf("\nEnter ciphertext: \n"); if (fgets(buf, sizeof buf, stdin) == NULL) Handle_EOF(); char *p = buf; int n; while (sscanf(p, "%d%n", &sourceArr[i], &n) == 1) { i++; p += n; } for (int j = 0; j < i; j++) { printf("%d\n", sourceArr[j]); } 

On success, scanf returns the number of items of the argument list successfully filled. This count can match the expected number of items or be less (even zero) due to a matching failure, a reading error, or the reach of the end-of-file.

You could change it to:

#include <stdio.h> #include <string.h> int main() { int sourceArr[500]; int i = 0; printf("\nEnter ciphertext: \n"); while (scanf("%d", &sourceArr[i++]) == 1); for (int j=0;j<i-1;j++) { printf("%d\n", sourceArr[j]); } } 

Then if you enter: 1 2 3 4 5 6 x (and hit enter)

It will display as you want.

If you don't like the 'x' you could use this while line:

while (scanf("%d", &sourceArr[i++]) != EOF); 

and then type something like: 12 23 345 554 (hit enter) and then (ctrl+z) in windows or (ctrl+d) in unix.

see this thread: End of File(EOF) of Standard input stream (stdin)

ctrl+z explicitly makes scanf return EOF because the console has no EOF and needs to be sent this way.

scanf returns the number of items successfully scanned. Try the below code:

 #include <stdio.h> int main() { int sourceArr[500]; int i = 0; int sc =0; //scanned items int n=3; // no of integers to be scanned printf("\nEnter ciphertext: \n"); while(sc<n){ sc += scanf("%d",&sourceArr[i++]); } for (int j=0;j<i;j++) { printf("%d\n", sourceArr[j]); } }