Doing BMI calculations I’m not getting just the result 80

Question

#include <stdio.h>
#include <math.h>

int main() 
{      
    float peso,altura,imc;
    imc=0;
    printf("digite seu peso ?");
    scanf("%f",&peso);
    printf("digite sua altura? ");
    scanf("%f",&altura);
    imc= (peso/pow(altura,2 )); //usando a função pow
    printf(" IMC igual a  %10.2f ",imc);

    return 0;
}

and without using the function pow

#include <stdio.h>
#include <math.h>

int main() 
{      float peso,altura,imc;
   imc=0;
    printf("digite seu peso ?");
    scanf("%f",&peso);
    printf("digite sua altura? ");
    scanf("%f",&altura);   // usando a função pow
    imc= (peso/altura*altura) ; // sem a função pow
    printf(" IMC igual a  %10.2f ",imc);

    return 0;
}

Answer 1

In the first test it was not possible to reproduce its problem:

https://ideone.com/m4IVad

The second is basic math error.

First you divide weight by height, then you multiply by height:

     peso/altura*altura
// 1 ----^
// 2 -----------^

The result, guess what? The time will come¹...

See the difference with the parentheses in the appropriate place:

imc = peso/(altura*altura);

https://ideone.com/LTEK5K

_{^{1. except for rounding differences which are not applicable in this financial year.}}.