Program #10 (U1): Absolute Value (no library)
Task: Read an integer and print its absolute value without using library functions. If it is negative, multiply by -1; otherwise leave unchanged.
/* Program: Absolute Value (no library) — U1 What it does: - Reads an integer n. - If n is negative, makes it positive by multiplying by -1. - Prints the absolute value. Note: - Works for typical 32-bit int ranges. Beware of the corner case INT_MIN (-2147483648) on two's-complement systems, where -INT_MIN cannot be represented as +2147483648 in a 32-bit int. For 1st year, this detail can be ignored.*/
#include <stdio.h>
int main(void) {
int n;
printf("Enter an integer: ");
if (scanf("%d", &n) != 1) {
printf("Invalid input. Please enter a valid integer.\n");
return 0;
} /* Core logic: if negative, flip the sign */
if (n < 0) {
n = -n; } printf("Absolute value = %d\n", n);
/* Examples:
Input: 42 -> Absolute value = 42 Input: -17 -> Absolute value = 17 Input: 0 -> Absolute value = 0*/
return 0;
}