Doubt in variable manipulation in C

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The following code uses the decision structure to choose the command consistent with the operation chosen by the user.

How could I simplify that? I tried to modularize instruction printf but I couldn’t.

#include <stdio.h>

main(){
    char operador = ' ';
    float valor1, valor2;
    printf("Entre com um tipo de operacao a ser realizada (+,-,*,/), o primeiro valor e o segundo valor\n");
    scanf("%c %f %f", &operador, &valor1, &valor2);
    if (operador == '+'){
        printf("Resultado da soma %.2f", valor1+valor2);
    }
    else if (operador =='-'){
        printf("Resultado da subtracao %.2f", valor1-valor2);
    }
    else if (operador =='*'){
        printf("Resultado da multiplicacao %.2f", valor1*valor2);
    }
    else{
        printf("Resultado da divisao %.2f", valor1/valor2);
    }

    printf("\n\n");
    system ("pause");

}

How it would look Modularized?

printf("Digite um tipo de operacao(+,-,*,/) e em seguida o primeiro valor e o segundo valor\n");
scanf("%c %d %d", &o, &x, &y);
    if(o=='+'){
        op=x+y;

          }
    else if (o=='-'){
        op=x-y;

          }
    else if (o=='*'){
        op=x*y;

          }
    else{
        op=x/y;

        }

    if(op==x+y && op==x-y && op==x*y  &&  op==x/y){
              printf("O resultado e:%d",op );
c
  • 1

    In my opinion, it’s simple enough and doesn’t need to change. Of course, someone might even suggest complicated things, like creating a mapping of operations -> function/message, or saying that "better use a switch" (it is not), but all this is wanting to complicate by chance, it does not need it. By the way, why do you think it is complicated?

  • I didn’t want to have to repeat that much printf for each decision. I’m testing ideas and mine was modulating it. I’d look like this but it’s not working...

  • https://ideone.com/UZKqP7

  • I asked the question as if

  • Really complicated in this case, but thank you for illuminating my idea! KKK

1 answer

3


If you only want to make one printf in the end, then you have to take all the information that changes (in this case, the name of the operation and the result) and set it according to the chosen operation. At the end, you print the result:

char operador;
float valor1, valor2;
printf("Entre com um tipo de operacao a ser realizada (+,-,*,/), o primeiro valor e o segundo valor\n");
scanf("%c %f %f", &operador, &valor1, &valor2);

// o nome da operação e o resultado variam conforme a operação escolhida
char *operacao = NULL;
float resultado;
if (operador == '+') {
    operacao = "soma";
    resultado = valor1 + valor2;
} else if (operador == '-') {
    operacao = "subtracao";
    resultado = valor1 - valor2;
} else if (operador == '*') {
    operacao = "multiplicacao";
    resultado = valor1 * valor2;
} else if (operador == '/') {
    operacao = "divisao";
    resultado = valor1 / valor2;
}

if (operacao != NULL)
    printf("Resultado da %s: %.2f\n", operacao, resultado);
else // pode ser digitada uma operação inválida, então trate este caso também 
    printf("Operação inválida\n");

Note that I also handled the case that the typed operation is invalid. In your code, anything other than +, - or * fell apart.

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