Write a program without using library functions ?

C Standard library functions or simply C Library functions are inbuilt functions in C programming.
The prototype and data definitions of the functions are present in their respective header files, and must be included in your program to access them.
If you want to use printf() function, the header file <stdio.h> should be included. For example,

Copy String Manually Without Using strcpy()

In this C Program we have to copy the string without using library functions.

Sample Code

[pastacode lang=”c” manual=”%23include%20%3Cstdio.h%3E%0Aint%20main()%0A%7B%0A%20%20%20%20char%20str1%5B100%5D%2C%20str2%5B100%5D%2C%20j%3B%0A%0A%20%20%20%20printf(%22Enter%20the%20string%20str1%3A%20%22)%3B%0A%20%20%20%20scanf(%22%25s%22%2Cstr1)%3B%0A%0A%20%20%20%20for(j%20%3D%200%3B%20str1%5Bj%5D%20!%3D%20’%5C0’%3B%20%2B%2Bj)%0A%20%20%20%20%7B%0A%20%20%20%20%20%20%20%20str2%5Bj%5D%20%3D%20str1%5Bj%5D%3B%0A%20%20%20%20%7D%0A%0A%20%20%20%20str2%5Bj%5D%20%3D%20’%5C0’%3B%0A%20%20%20%20printf(%22String%20str2%3A%20%25s%22%2C%20str2)%3B%0A%0A%20%20%20%20return%200%3B%0A%7D” message=”” highlight=”” provider=”manual”/]

Output

[pastacode lang=”c” manual=”Enter%20the%20String%20str1%3A%20Wikitechy%0A%20String%20str2%3A%20Wikitechy” message=”” highlight=”” provider=”manual”/]

Write a program without using library functions ?