Problem $3(15$ pts$)$

$(1)$ The following program executes in serial mode. Please use OpenMP's instructions to turn it into a parallel program with $4$ threads. $($Add your code in the grey area$)$

$```$

void main$()$

$\{$

int i;

double x$=0$;

for $($i$=0$; i $<mtext></mtext><mn>1</mn><mn>0</mn><mn>0</mn><mn>0</mn>$; i$++)$

$\{$

x $=$ i$*0\mathrm{.}5$;

$\}$

$\}$

$```$

$(2)$ The following OpenMP code is a multi$-$thread program. However, it has potential issue for synchronization. Please point out the problem and correct it$.$

$```$

void main$()$

$\{$

int i;

double sum$=0$;

#pragma omp parallel for

for $($i$=0$; i$<mtext></mtext><mn>1</mn><mn>0</mn><mn>0</mn><mn>0</mn>$; i$++)$

sum$++$;

$\}$

$```$