how to get input int in c code example

Example 1: how to make sure input is integer c

#include <string.h>  

bool isNumber(string s) 
{ 
    for (int i = 0; i < strlen(s); i++) 
        if (isdigit(s[i]) == false) 
            return false; 
  
    return true; 
}

Example 2: get int from user c

#include <stdio.h>

int n;
scanf("%d",&n);