Pointers in C programming second semester

Pointers in C programming second semester

• 1.
  Pointers in C
• 2.
  Introduction to Pointers •Holds the address of another variable. • Advantages: efficient arrays, multiple return values, dynamic memory, linked structures, faster execution. • Disadvantage: program may crash if memory unavailable. • Operators: & (address), * (dereference).
• 3.
  Declaring a Pointer Syntax:data_type *ptr_name; Examples: int *p; float *temp; int x=10; int *ptr=&x; printf("%d", *ptr);
• 4.
  Program: Basic PointerUsage #include<stdio.h> void main() { int x=99; int *ptr=&x; printf("Value = %dn", *ptr); printf("Address = %pn", ptr); } Output: Value = 99 Address = 0x7ffd...
• 5.
  Program: Add 2Floats #include<stdio.h> void main() { float n1,n2,sum=0.0; float *p1=&n1,*p2=&n2,*ps=&sum; scanf("%f,%f",p1,p2); *ps=*p1+*p2; printf("%f+%f=%f",*p1,*p2,*ps); } Output: 3.2+2.3=5.5
• 6.
  Program: Positive/Negative #include<stdio.h> void main(){ int num,*p=&num; scanf("%d",p); if(*p>0) printf("Positive"); else if(*p<0) printf("Negative"); else printf("Equal"); }
• 7.
  Null Pointers Special valuepoints nowhere. int *ptr=NULL; if(ptr==NULL){ /* safe */ }
• 8.
  Generic (Void) Pointers Canpoint to any type. void *gp; int x=10; char c='A'; gp=&x; printf("%d",*(int*)gp); gp=&c; printf("%c",*(char*)gp);
• 9.
  Passing Arguments toFunctions • Pass addresses to functions. • Function dereferences pointers to modify caller’s vars. Example: swap, sum, largest number.
• 10.
  Program: Sum ofTwo Integers #include<stdio.h> void sum(int *a,int *b,int *t){ *t=*a+*b; } int main(){ int n1,n2,t; scanf("%d,%d",&n1,&n2); sum(&n1,&n2,&t); printf("Total=%d",t); }
• 11.
  Applications of Pointers •Arrays & Strings • Function Pointers • Structures • File Handling • Efficient Parameter Passing • Dynamic Data Structures • Callback Functions