Q.Write a C program to accept two numbers and check whether they are equal or unequal. The textbook presents this worked program, transcribed exactly as printed (including its printed errors):

#include<stdio.h>  
void main()  
{  
    int m, n;  
printf("Enter the values of M, N\n");  
scanf("%d%d", &m, &n);  
if (m==n)  
printf("Enter the values of M, N\n");  
else  
printf("M and N are not equal\n");  
}  
/*End of main()*/  

Sample output printed in the textbook:

Run 1                            Run 2  
Enter the value of M and N       Enter the value of M and N  
55                               28  
55                               58  
M and N are equal                M and N are not equal  

By default a C program runs its statements one after another, but decision (conditional) control statements let it choose between alternative paths depending on a condition. They are the basis of all decision-making programs.

• if statement - executes a block only when its condition is true; if the condition is false the block is skipped.

  if (condition)
      statement;
  

• if-else statement - provides two alternatives: one block runs when the condition is true, the other when it is false.

  if (condition)
      statement1;
  else
      statement2;
  

• Nested-if / else-if ladder - an if (or if-else) placed inside another, used to test several conditions in turn. This is how a program picks the largest of three numbers, or grades a value into ranges such as short, average and tall. …