problem in C with rest of the division

Question

Develop a program that scans ten elements of an A-matrix vector type. Construct a matrix B of the same type, observing the following law of formation: if the value of the index is even, the value must be multiplied by 5, being odd, must be added with 5. At the end show the content of matrix A and B.

When I go to compile the program shows the following error.

2417 19 C: Users User Documents DEV C++ aula03.cpp [Error] expected Primary-Expression before ';' token

It highlights the line "Resp = Indice %;" as the line with error. I am grateful for your help.

    int matriza[10];
    int matrizB[10];
    int indice;
    int resp;

    for( indice = 0; indice < 10; indice++ )
     {
     printf("digite um valor numerico inteiro: ");
     scanf ("%d", &matriza[indice]);
     }

    for(indice = 0; indice < 10; indice++)
     {
     resp = indice %;
     if (resp == 0)
     matrizB[indice] = matriza[indice] * 5;
     else
     matrizB[indice] = matriza[indice] + 5;
     }

    for(indice = 0; indice < 10; indice++)
     printf ("\nConteudo da matriz a indice %d = %d", indice,           matriza[indice]);

    for(indice = 0; indice < 10; indice++)
     printf ("\nConteudo da matriz B indice %d = %d", indice, matrizB[indice]);

Answer 1

Just missed you make the split by 2 to know if it’s even or not. You can’t stop the math expression in between.

#include <stdio.h>

int main(void) {
    int matriza[10];
    int matrizB[10];
    int indice;
    for (indice = 0; indice < 10; indice++) {
        printf("digite um valor numerico inteiro: ");
       scanf ("%d", &matriza[indice]);
     }
    for (indice = 0; indice < 10; indice++) {
        if (indice % 2 == 0) matrizB[indice] = matriza[indice] * 5;
        else matrizB[indice] = matriza[indice] + 5;
    }
    for (indice = 0; indice < 10; indice++) printf ("\nConteudo da matriz a indice %d = %d", indice, matriza[indice]);
    for (indice = 0; indice < 10; indice++) printf ("\nConteudo da matriz B indice %d = %d", indice, matrizB[indice]);
}

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

I didn’t check if the rest of the logic is right, I just solved the question problem. nor did I simplify and organize the code better. The code is pretty bad to read. try to learn to do things in a more organized way and avoid silly mistakes like this.

Answer 2

resp = indice %;

The line is not valid, the expression is incomplete, an argument is missing. From the statement of the question I suggest number 2 because there is a need to find out if the number is even or not. The error posted can be fixed like this.

resp = indice % 2;

Answer 3

The operator % provides you the rest of the division of a number (the dividend) by another number (the divisor). So, you need to provide the two numbers to the operator. Some examples:

5 % 2 = 1
6 % 4 = 2
9 % 3 = 0

The error occurred due to the fact that you only provided the dividend to the operator. Missing the divisor. It would be something like 5 %, which makes no sense to the compiler.

To fix the error, just provide the splitter to the operator %:

resp = indice % 2;

I hope I’ve clarified your doubt and helped you correct your mistake.