ตัวชี้เป็นตัวแปรที่เก็บที่อยู่ของตัวแปรอื่น
ไวยากรณ์สำหรับพอยน์เตอร์มีดังนี้ −
pointer = &variable;
ตัวอย่าง
ต่อไปนี้เป็นโปรแกรม C สำหรับแนวคิดของพอยน์เตอร์โดยใช้ภาษา C -
#include<stdio.h> void main(){ //Declaring variables and pointer// int a=2; int *p; //Declaring relation between variable and pointer// p=&a; //Printing required example statements// printf("Size of the integer is %d\n",sizeof (int));//4// printf("Address of %d is %d\n",a,p);//Address value// printf("Value of %d is %d\n",a,*p);//2// printf("Value of next address location of %d is %d\n",a,*(p+1));//Garbage value from (p+1) address// printf("Address of next address location of %d is %d\n",a,(p+1));//Address value +4// //Typecasting the pointer// //Initializing and declaring character data type// //a=2 = 00000000 00000000 00000000 00000010// char *p0; p0=(char*)p; //Printing required statements// printf("Size of the character is %d\n",sizeof(char));//1// printf("Address of %d is %d\n",a,p0);//Address Value(p)// printf("Value of %d is %d\n",a,*p0);//First byte of value a - 2// printf("Value of next address location of %d is %d\n",a,*(p0+1));//Second byte of value a - 0// printf("Address of next address location of %d is %d\n",a,(p0+1));//Address value(p)+1// }
ผลลัพธ์
เมื่อโปรแกรมข้างต้นทำงาน มันจะให้ผลลัพธ์ดังต่อไปนี้ −
Size of the integer is 4 Address of 2 is 6422028 Value of 2 is 2 Value of next address location of 2 is 463824 Address of next address location of 2 is 6422032 Size of the character is 1 Address of 2 is 6422028 Value of 2 is 2 Value of next address location of 2 is 0 Address of next address location of 2 is 6422029