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What is static variable in C Programming?

Answer: Static variable in C programming is the variable which value persists between different function calls throughout the life cycle of the program.

For example, in the below function staticVarCount (), the s is a static variable, and when we make a call again and again, its value will be increased e.g.1,2,3…and so on. Value of s will persist, even though its scope is within the function itself.

Static variable code example in C

staticVarCount(){
	static int s = 0;
	++s;
	printf("Static Variable:%d\n",s);
}

Non static variable

Below is the same function implementation with non static variable s. when we make multiple calls, its value will be always 1 as variable s will die as soon as control goes out of the function.

nonStaticVarCount(){
	int i = 0;
	++i;
	printf("Non Static Varable:%d\n",i);
}

Complete code of Static Variable and Non Static variable in C

 

//Function with static variable
staticVarCount(){
	static int s = 0;
	++s;
	printf("Static Variable:%d\n",s);
}

//same function with non static variable
nonStaticVarCount(){
	int s = 0;
	++s;
	printf("Non Static Varable:%d\n",s);
}

int main(){
	
	staticVarCount();
	staticVarCount();

	nonStaticVarCount();
	nonStaticVarCount();

	return 0;
}

Output:

Static Variable:1
Static Variable:2
Non Static Varable:1
Non Static Varable:1

NOTES:

  • Static variables in c and  c++ automatically get initialize by zero, if we don’t initialize it by zero or some number.
  • There can be a Global and local Static variable in c. Local static variable will be always taken on priority within the scope. Do read example below.

Global and Local Static variable C Code Example

#include 

static int s = 5;//Global Static varialbe

int main(){
	
	static int s = 10;//Local Static varialbe with same name

	printf("Value of s:%d\n",s);

	return 0;
}

Output:
Value of s:10


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