Question

1. [C++ Language] Look at the following code and comment each line about how it works with pointer.

int i = 33;

double d = 12.88;

int * iPtr = &i;   

double * dPtr = &d; //

iPtr = &d;   //

dPtr = &i;   //

iPtr = i;    //

int j = 99;

iPtr = &j; //

Answer 1

check out the solution.

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#include <iostream>

using namespace std;

int main() {
int i = 33; // declare an int variable and assign 33 to it
double d = 12.88; // declare a double variabe and assign 12.88 to it
int * iPtr = &i; // save address of int variable 'i' in int type pointer iPtr that is int type pointer iPtr now points to 'i' address
double * dPtr = &d; // save address of double variable 'd' in double type pointer dPtr that is double type pointer dPtr now points to 'd' address
iPtr = &d; // save memory address of 'd' in pointer iPtr - this throws error - as 'd' is double type and iPtr is of int type so compilation error
dPtr = &i; // save memory address of 'i' in pointer dPtr - this throws error - as 'i' is int type and dPtr is of double type so compilation error
iPtr = i; // save value of 'i' in pointer iPtr - this throws error - as 'i' is int type and iPtr is of int type pointer - so compilation error
int j = 99; // declare an int variable and assign 99 to it
iPtr = &j; // save address of 'j' to iPtr which both are of int type
}

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Errors after compilation :

jdoodle.cpp: In function 'int main()': jdoodle.cpp:10:12: error: cannot convert double*) to 'int*) in assignment 10 iPtr = &d; // save memory address of 'd' in pointer iPtr - this throws error as 'd' is double type and iPtr is of int type so compilation error double* jdoodle.cpp:11:12: error: cannot convert 'int*) to 'double*) in assignment 11 dPtr = &i; // save memory address of 'i' in pointer dPtr - this throws error as 'i' is int type and dPtr is of double type so compilation error int* jdoodle.cpp:12:12: error: invalid conversion from 'int' to 'int*) (-fpermissive) 12 iPtr = i; // save value of 'i' in pointer iPtr - this throws error - as 'i' is int type and iPtr is of int type pointer - so compilation error int

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