Why is an expression with remainder and multiplication giving the wrong result?

Question

Why is an expression with remainder and multiplication giving the wrong result?

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#1 by (6 votes)

3

Why is this code giving -2 instead of 7?

 #include <stdio.h>

 main()
 {
   printf("%i\n", 105 % 3*4 - 3*4 % (101 / 10));
   system("pause");
 }

operadores c

asked by anonymous 06.08.2016 / 20:22

1 answer

Make Div appear 4 seconds after the site is loaded [duplicate] Single instance of Class C #

score 6 · Accepted Answer

I did so and gave 7:

#include <stdio.h>

int main() {
    printf("%i\n", 105 % (3 * 4) - (3 * 4) % (101 / 10));
    return 0;
}

See working on ideone .

You've probably interpreted the expression without considering precedence and associativity of operators . The rest operator has the same precedence of multiplication and associativity by the left, so in an expression with the two operators what appears first will be executed. To increase the precedence of an operator, you must use the high-priority parent operator.

The second pair of parentheses is not necessary, I put it just to help better see the separation. The last pair, which already existed, solves the problem of precedence that could exist.