Why can’t I change a variable in C by performing an arithmetic operation with it?

Question

I’m not getting the expected result:

libraries ...

int main (void){
    float c,r;
    setlocale(LC_ALL,"");
    printf("Digite o salário\n");
    scanf("%f",&c);
    printf("Digite o reajuste percentual:\n");
    scanf("%f",&r);
    r=r*0,01;
    c=(c* r)+c;
    printf("Salário reajustado: %.2f\n",c);
    return 0;
    }

The result always comes out with the first reading of the variable c, which would be the starting salary, as I do for it to be "updated" in the operation just below without having to add more variables?

As follows it works:

libraries ...

int main (void){
    float c,r,n;
    setlocale(LC_ALL,"");
    printf("Digite o salário\n");
    scanf("%f",&c);
    printf("Digite o percentual de reajuste:\n");
    scanf("%f",&r);
    n=c+r*c;
    printf("Salário reajustado: %.2f\n",n);
    return 0;
    }

But in addition to the additional variable, the user would have to add the readjustment between a real number from 0 to 1, not to mention that I’m sure I’ll need to use this in the future. How can I solve?

Answer 1

Do not use comma to decimals, use dot.

#include <stdio.h>

int main (void){
    float c, r;
    printf("Digite o salário\n");
    scanf("%f", &c);
    printf("Digite o reajuste percentual:\n");
    scanf("%f", &r);
    r *= 0.01;
    c = c * r + c;
    printf("Salário reajustado: %.2f\n", c);
}

Behold working in the ideone. And in the repl it.. Also put on the Github for future reference.

Just be careful that this code has several other problems, don’t think that just because it’s working it’s right.