How do I save integers read by getchar() to an array? - c

Question

I am trying to make a program that will use getchar() to read three integers and store it in an array but something is wrong in my code.
#include <stdio.h>
int main( )
{
printf("Please enter three digit number 100 to 999: ");
int numEntered[2];
numEntered = getchar();
for (int i = 0; i<3; i++) {
printf("%d", numEntered[i])
}
}

Answer 1

Try this:
#include <stdio.h>
int main(){
printf("Please enter three digit number 100 to 999: ");
int numEntered[3];
for (int i = 0; i<3; i++){
scanf("%d", &numEntered[i]);
printf("%d", numEntered[i]);
}
return 0;
}
you need to read a value inside the for loop! Second thing, by reading with getchar(), you are getting the ascii value of the character, so.. if you read "1" and print with %d, you actually printing 49!
See the ascii table here: http://www.asciitable.com/index/asciifull.gif

Answer 2

let's try and and think about the problem here:
do you want to read and store an integer value? if yes -> use scanf
do you want to read a number digit by digit? if yes -> use getchar
do you want to make sure what you read has exactly 3 digits? if yes...what do you do when it does not?
if reading digit by digit, make sure you are reading numbers; getchar reads characters -> use atoi funtion or check ascii value;
Putting it all together(some assumptions were made):
int main()
{
char digits[3]; // don't use ints to store chars...
printf("enter the 3 digit number - 100 to 999: ");
for (int i=0;i<3;i++) // only the first 3 chars are read
{
char c = getchar();
if (char < '0') || (char > '9')
{
printf("invalid digit!");
exit(0);
}
digits[i] = c;
}
printf("the number entered is: %c%c%c", digits[0],digits[1],digits[2]);
}

Answer 3

You don't use getchar to get integer values.
Use scanf() instead.
Try this:
#include <stdio.h>
int main( )
{
printf("Please enter three digit number 100 to 999: ");
int numEntered[3];
for (int i = 0; i<3; i++){
scanf("%d",&a[i]);
printf("%d", numEntered[i]);
}
}

Answer 4

numEntered = getchar();
(1) It can not be assigned to the array itself.
(2) getchar() reads one character.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
int main(void){
char digits[4] = {0};//4: 3 character + NUL character
int ch, value;
do {
printf("Please enter three digit number 100 to 999: ");
for(int i = 0; i < 3 && (ch = getchar()) != '\n' && ch != EOF; ++i){
digits[i] = ch;
}
if(ch != '\n')
while((ch = getchar()) != '\n')
if(!isspace(ch))//invalid input
*digits = 0;
value = atoi(digits);
} while(value < 100 || 999 < value);
char *rotate_left(char digits[4]);
printf("%d\n", value);
printf("%d\n", atoi(rotate_left(digits)));
printf("%d\n", atoi(rotate_left(digits)));
return 0;
}
char *rotate_left(char digits[4]){
char temp = digits[0];
digits[0] = digits[1];
digits[1] = digits[2];
digits[2] = temp;
return digits;
}