Thread: About scanf

This is a BMI Calculator..That's no problem when using correctly.(Typing correct number)
But, if I'm a bad guy and typing some letters…It would show “Don't trick me, Again(in Meters):” repeatedly but wouldn't let me typing anything(Like just skip "scanf")

Code:

#include<stdio.h>
#include<stdlib.h>


int main(void)
{
    float height = 0, weight = 0, BMI = 0;
    int OK = 0;
    printf("Welcome to BMI calculator.\nPlease type your height first(in Meters):");
    while(!OK){
        OK = scanf("%f", &height);
        if(height >0 && OK){
            printf("\nWell, not so tall :)\nAnd..Your Weight(in Kilograms):");
            OK = scanf("%f", &weight);
            while(weight <= 0 || !OK) {
                printf("\nAgain(in Kilograms):");
                OK = scanf("%f", &weight);
            }
        } else {
            printf("\nDon't trick me, Again(in Meters):");
            OK = scanf("%f", &height);   //be skipped?
        }
        if(!height || !weight) OK = 0;
    }
    BMI = weight / (height * height);
    printf("\nOk..your BMI is: %.2f\n", BMI);
    system("pause");
    return 0;
}