Print number for each second-CodePudding

#include <stdio.h>
#include <wiringPi.h>
#include <softPwm.h>


int main(void)
{
    wiringPiSetupGpio();
    
    for(int i = 0 ; i <50; i  )
    {   
        if ( i%10 == 1)
        {
            printf("\n");
        }
    
        printf("%d  ", i);
        
        delay(1000);
        
    }
    
    
    return 0;
}

I'm working in rasberry pi environment. I want to print a number for each 1 second. But this code did not print a number one by one but print 10 numbers for each 10 seconds. This code gives 10 numbers in line at once. What's the problem??

CodePudding user response：

The problem is probably that the output buffer is not being flushed.

I suggest that you call fflush( stdout ); before the delay(1000); function call.

CodePudding user response：

The stdout channel is line buffered by default. This means that data sent to stdout won't necessarily appear until a newline character is printed.

If you call fflush(stdout), any buffered output will be immediately printed.

printf("%d  ", i);
fflush(stdout);

CodePudding user response：

in order to print the values at the running time using printf you need to add \n so try this may work.

#include <stdio.h>
#include <wiringPi.h>
#include <softPwm.h>


int main(void)
{
    wiringPiSetupGpio();
    
    for(int i = 0 ; i <50; i  )
    {   
        if ( i%10 == 1)
        {
            printf("\n");
        }

// a `\n` added at the end of the string!
        printf("%d  \n", i);
        
        delay(1000);
        
    }
    
    
    return 0;
}

for more info read this question's answer