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Somor
Joined: 18 Dec 2014
Posts: 12
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| Problem with if-else condition... |
 Posted: Fri May 29, 2015 8:42 am |
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| Code: | #include <keycode test.h>
int key[4]={3,7,0,1};
int pressed[4]={0,0,0,0};
int column=0;
int row=10;
int num=0;
void out()
{
if (column==0) output_a(254);
if (column==1) output_a(253);
if (column==2) output_a(251);
}
void press(void)
{
int pr=0;
if(num<4)
{
pr = (column+1) + 3*row;
if(pr == 11) pressed[num] = 0;
else pressed[num] = pr;
printf("%d ", pressed[num]);
row = 10;
num++;
}
}
void read()
{
int i=0;
int in;
for(i=0;i<4;i++)
{
in = PIN_B0 + i;
if(input(in) == 0)
{
delay_ms(32);
while(input(in)==0)
{
row = i;
}
}
}
if(row!=10) press();
}
void main() {
int num=0;
int i;
int sum=0;
while (TRUE)
{
if(num==4)
{
for(i=0;i<4;i++)
{
sum = sum + (key[i] - pressed[i]);
}
if(sum==0) output_d(4);
num = 0;
}
if(num<4)
{
for(column=0;column<3;column++)
{
out();
read();
}
}
}
}
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I am using PIC18F45K22 with external oscillator at 8MHz.
The problem is that it never executes the if(num==4) condition.
Originally i tried with if(num<4) ........ (where it outputs columns and reads rows) else verify() (function that substracts key[i] and press[i]). the problem is that it never checks the two arrays, it never goes to verify function... |
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humbertokramm
Joined: 29 May 2015
Posts: 7
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| Posted: Fri May 29, 2015 8:58 am |
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I think the bug is because of you declare twice the same variable "num".
It is declared as Global and Local (on the main function)
_________________
Humberto Kramm
looking for questions to answer 42 |
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jeremiah
Joined: 20 Jul 2010
Posts: 1349
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| Posted: Fri May 29, 2015 10:18 am |
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Yes.
In C, if variables of two different scopes (global and local) are available in the current scope, then the local one takes precedence and the global one cannot be used in that scope.
Also, as a side advice, it is a really good idea to avoid using int, short, long, etc and instead use the defined: int32, int16, and int8. The size of int can change between parts, but int32, int16, and int8 are always the same size. |
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