how to make sure input is integer c

To make sure the input is an integer in C, you can use the scanf function to read the input and check if it returns 1. Here's an example:

#include <stdio.h>

int main() {
    int num;
    printf("Enter an integer: ");
    if (scanf("%d", &num) != 1) {
        printf("Invalid input. Please enter an integer.\n");
        return 1;
    }
    printf("You entered: %d\n", num);

    return 0;
}

This code prompts the user to enter an integer, reads the input using scanf, and checks if the return value is 1. If the return value is not 1, it means that the input was not a valid integer. In that case, it prints an error message and returns 1. Otherwise, it continues with the rest of the code.