Conditional operator ?: not working

Question

I’m having trouble using the ?:

 #include <stdio.h>

 int main()
 {
 int num1 = 10;
 int num2 = 20;
 int resposta;

 num1 < num2 ? printf("sim\n") : printf("nao\n");

 // O erro acontece aqui ao compilar

 num1 < num2 ? resposta = 10 : resposta = -10;

 printf("%i\n", resposta);


 return 0;
 }

Answer 1

Conditional operator accepts only expressions and does not statements, so it doesn’t work. Both can best be written using conditional operator only at the part that actually varies, and that is an expression.

#include <stdio.h>

int main() {
    int num1 = 10;
    int num2 = 20;
    printf(num1 < num2 ? "sim\n" : "nao\n");
    int resposta = num1 < num2 ? 10 : -10;
    printf("%i\n", resposta);
}

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

Answer 2

Use normal if Else

if(num1 < num2)
    resposta = 10;
else
    resposta = -10;