1. C Program to find the biggest and smallest among 4 numbers using nested if.

//1. C Program to find the biggest and smallest among 4 numbers using nested if.
#include<stdio.h>
void main()
{
    int a=400,b=300,c=20,d=200,big,small; //Declare variables and initialize them.
    clrscr();    //Clear the screen.
    if((a>b && a>c) && a>d)      //Check whether a is greater than b,c and d.
    {
        big=a;
        if(b<c && b<d)       //Check whether b is lesser than c and d.
            small=b;
        else if(c<d)               //Check whether c is lesser than d.
            small=c;
        else
            small=d;

    }
    else if(b>c && b>d)             //Check whether b is greater than c and d.
    {
        big=b;
        if(a<c && a<d)             //Check whether a is lesser than c and d.
            small = a;
        else if(c<d)               //Check whether c is lesser than d.
            small = c;
        else
            small = d;

    }
    else if(c>d)                       //Check whether c is greater than d.
    {
        big=c;
        if(a<b && a<d)          //Check whether a is lesser than b and d.
            small=a;
        else if(b<d)               //Check whether b is lesser than d.
            small=b;
        else
            small=d;

    }
    else
    {
        big=d;
        if(a<b && a<c)
            small=a;
        else if(b<c)
            small=b;
        else
            small=c;
    }
    printf("Biggest Number=%d \t Smallest Number=%d",big,small);
    getch();
}