# Code for D

```Code for Da
#include&lt;stdio.h&gt;
int main()
{
int x,y=1,num;
printf(&quot;Enter a number: &quot;);
scanf(&quot;%d&quot;,&amp;num);
for(x=1;x&lt;=num;x++)
y=y*x;
printf(&quot;Factorial value is: %d&quot;,y);
return 0;
}
Code for Db
#include&lt;stdio.h&gt;
int power(int a,int b);
main()
{
int base,expo,result;
printf(&quot;\t\t\tEnter a number for base: &quot;);
scanf(&quot;%d&quot;,&amp;base);
printf(&quot;\t\t\tEnter a number for exponent: &quot;);
scanf(&quot;%d&quot;,&amp;expo);
result=power(base,expo);
printf(&quot;\nThe Result of %d^%d is : %d&quot;,base,expo,result);
}
int power(int x,int y)
{
int val,i;
val=1;
for(i=1;i&lt;=y;i++)
{
val=val*x;
}
return val;
}
Code for Dc
#include &lt;stdio.h&gt;
#include &lt;math.h&gt;
void func(int a, int b, int c, int d, int e, int *sum, float *avg, float *std)
{
*sum = a + b + c + d + e;
*avg = *sum / 5;
*std = sqrt((((a - *avg)*(a - *avg)) + ((b - *avg)*(b - *avg)) + ((c - *avg)*(c - *avg))) / 5.0);
}
int main( )
{
float avg, std;
int a, b, c, d, e, sum;
printf(&quot;\n\t\t\tInput 5 comma seperated integers: &quot;);
scanf(&quot;%d,%d,%d,%d,%d&quot;, &amp;a, &amp;b, &amp;c, &amp;d, &amp;e);
func(a, b, c, d, e, &amp;sum, &amp;avg, &amp;std);
printf(&quot;\n\t\t\tThe sum is %d\n\t\t\tThe average is %f\n\t\t\tThe standard deviation is %f\n&quot;, sum, avg,
std);
return 0;
}
Code for Dd
void main()
{
int a,b,c,full;
float av,perc;
printf(&quot;\nEnter the marks received by the student in 3 subjects and the total possible marks
for 1 paper&quot;);
scanf(&quot;%d%d%d%d&quot;,&amp;a,&amp;b,&amp;c,&amp;full);
calc(a,b,c,full,&amp;av,&amp;perc);
printf(&quot;\nThe average marks is %f.\nThe percentage is %f&quot;,av,perc);
}
calc(int i,int j,int k,int full,float *ave,float *perce)
{
*ave=(i+j+k)/3.0;
*perce=(*ave/full)*100.0;
}
```