1.In “nested if” control statement, if condition 1 is false, then condition 2 is checked and statements are executed if it is true.
If condition 2 also gets failure, then else part is executed.

For Example-:

	  #include<stdio.h>
	  void main()
	  {
	   int a,b,c;
	    printf("enter the no");
	    scanf("%d%d%d",&a,&b,&c);
	    if(a>b)
	    {
	    if(a>c)
	    {
	     printf("a is gretest");
		 }
		 else
		 {
		   printf("c is gretest");
		   }
		 }
		 if(b>c)
		 {
		 printf("b is gretest");
		 }
		  else
		  {
		   printf("c is gretest");
		  }
		 }