Variable percentage in c

Question

I have a problem with a simple code, I want to know how to calculate the percentage of a value.

EX: 1500 + 15% (in this case I know it is value = value*0.15)

However, the percentage value must be a variable informed by the user. So far I have the following code but I don’t think it will help.

#include <stdio.h>

//Escreva um programa que leia: o valor de uma aplicação, o
//percentual de rendimento mensal obtido por esta aplicação e o
//período do investimento; e retorne o valor da aplicação ao final do
//período de investimento.

int main (){

    float aplicacao = 0;
    float rendimento = 0;
    float ff = 0;
    int periodo = 0;
    int cont = 0;

    while (cont < periodo){
        ff = aplicacao + rendimento
        cont ++
    }

}

Answer 1

First you need the float value, that is, divide the percentage value by 100. Be careful with conversions ( int result = desc / 100 would result in 0, as decimals would be truncated when converting from float to int). With that, just do the multiplication.

Answer 2

One solution to this would be to receive an integer number and then divide it by 100 as well as in the code below:

  int Num;
  float percen;
  cout << "Lendo a porcentagem...: ";
  cin >> Num;
  percen = Num/100;

You can learn more about the methods Cin and Cout on the link: https://www.inf.pucrs.br/~pinho/PRGSWB/Streams/streams.html