C programming_ Day 1

Importance of Programming Language

• A programming language is an instruction set written machine understandable language that instructs computer to do the desired task. 
• A programmer writes source code text in the programming language to create programs. It is used to make all the computer programs and computer software to control the assign task in certain procedure.
• For example: Binary language, Assembly language, B, PASCAL, GOBAL, C, C++, C#, JAVA, Python, Go and etc.

Introduction to C language:

• C is a general-purpose high level language that was originally developed by Dennis Ritchie for the Unix operating system.
• It was first implemented on the Digital Equipment Corporation PDP-11 computer in 1972.
• It is an upgrade version of languages B and BCPL.

Steps to Learn Programming Language

//80% usually Means "excellent"
#include <stdio.h>
int main()
{   int n=80;
    char ch='a';
    printf("%d%% usually\n Means \?excellent\?\v",n);
    printf("Learn\t with durga\v");//Learn       with durga
    printf("Never stop learning\n");                        //Never stop learning
    printf("Food\rGuard");//\r-> carriage return ==>Good
    return 0;

}

Structure of C programming Language

Declaration and Initialization:

int a,b,c=10;
int a=2,b;
if(pf)
for
//#include <stdio.h> //printf and scanf
#include"stdio.h"//userdefined modification
int main()
{ 
  //  int a=7;
   // int a='c';//a=99
    int a=printf("Learn with Durga\n");//Learn with Durga
    printf("%d",a);//a=?
    return 0;
}

2.
#include<stdio.h>//userdefined modification
int main()
{ 
   int a=20;
   printf("%d\n",a); //20
   printf("%4d....\n",a); //__20
   printf("%-4d....\n",a);//20__
   printf("%6.5d....\n",a);//_00020
   printf("%-6.5d....\n",a);//00020_
    return 0;
}
Storage classes available in C:

• auto
• extern
• static
• register

auto:
#include <stdio.h>
int main()
{   auto int i=5;
    {
        auto int i=4;
        printf("%d\t",i);
        {
        auto int i=3;
        printf("%d\t",i);
        }
        printf("%d\t",i);
    }
     printf("%d",i);
    return 0;

}

static:
#include <stdio.h>
int main()
{   static int a=4;
    printf("%d\t",a--);//4 3 2 1
    if(a>0)
    main();
    return 0;

}

extern:
#include <stdio.h>
int main()
{   extern int a;//a=9
    printf("%d\t",a);//9
    a=10;
    printf("%d\t",a--);//10
    printf("%d\t",a);//9
    return 0;
}

a=9;
Classification of Datatype:

• Primitive datatype - int,float, double and char
• User defined datatype - typedef and enum
• Derived datatype: primitive derived - array and user-defined derived - structure and union

step 3: Instruction set

• Decision making statement - if else and switch
• Looping statement - while, do while and for