Solution: warning: ISO C90 forbids mixed declarations and code

If you get above warning means in your code operation code in between deceleration see below example

Invalid Code:
main(){
int a;
a = function1();
int b;
b = function2();
}

Valid Code:
main(){
int a;
int b;
a = function1();
b = function2();
} 

So write all declarations one place