C Program without using the Main() Function

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This is a C program to display function without using the main function.

Problem Description

This program displays function without using the main function.

Problem Solution

1. Use #define macro to rename the main.
2. Print the output and exit.

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Program/Source Code

Here is source code of the C Program to display function without using the main function. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

  1. /*
  2.  * C Program to display function without using the Main Function
  3.  */
  4. #include <stdio.h>
  5. #define decode(s,t,u,m,p,e,d) m##s##u##t
  6. #define begin decode(a,n,i,m,a,t,e)
  7.  
  8. int begin()
  9. {
  10.     printf(" helloworld ");
  11. }
Program Explanation

1. Use #define macro for doing this.
2. #define decode(s,t,u,m,p,e,d) m##s##u##t.
This code says, next time when decode is encountered with 7 parameters, replace it by the concatenation of the 4th,1st,3rd and 2nd argument.
3. #define begin decode(a,n,i,m,a,t,e). In this line the 4th, 1st, 3rd and 2nd argument are m, a, i and n respectively. So the main is replaced by begin.
4. Use function named begin and print the output as ” helloworld ” and exit.

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Runtime Test Cases
Output:
 
helloworld

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If you wish to look at other example programs on Simple C Programs, go to Simple C Programs. If you wish to look at programming examples on all topics, go to C Programming Examples.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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