Written: August 14, 2026 · Updated: August 15, 2026
Branching on the sign of a number is a classic first if-else lab in C and GTU coursework.
This walkthrough keeps the logic small and readable so you can type it, run it, and then change one input at a time to see what happens.
What you will build
Read one integer and print whether it is positive, negative, or exactly zero.
- Read an integer n
- If n > 0 print positive
- Else if n < 0 print negative
- Else print zero
Working C example
include <stdio.h>
int main(void) {
int n;
printf("Enter an integer: ");
if (scanf("%d", &n) != 1) return 1;
if (n > 0) {
printf("Positive\n");
} else if (n < 0) {
printf("Negative\n");
} else {
printf("Zero\n");
}
return 0;
}How the logic works
Read the program top to bottom: includes and main first, then the statements that change variables, then the print that proves the result.
If your output looks wrong, print the variables before and after the critical lines. That single habit catches most beginner bugs faster than rewriting the whole file.
Test 5, -3, and 0. Zero is the case beginners accidentally fold into “positive.”.
Keep learning
If this walkthrough on C Program to Check Positive, Negative, or Zero helped, open the code again and change one input or assumption. Small experiments beat rereading the same example.
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