How to catch a division by zero error in it? ++How to initialize variables in it?

In the C language, void pointers are implicitly converted to object pointer types. This functionmalloc()In C89the standard returns void *. In earlier versions of Cmalloc()Returns char *. In C ++In the language, by defaultmalloc()Returns an int value. Therefore, use explicit conversion to convert the pointer to an object pointer.

The following is the syntax for allocating memory in C language.

pointer_name = malloc(size);

Here,

pointer_name-to any name given to the pointer.

Size-the size of memory allocated in bytes.

The following ismalloc()C language example.

Example

#include <stdio.h>
#include <stdlib.h>
int main() {
　　　int n =　4, i,　*p, s = 0;
　　　p = malloc(n　*　sizeof(int));
　　　if(p == NULL) {
　　　　　　printf("\nError! memory not allocated.");
　　　　　　exit(0);
　　　}
　　　printf("\nEnter elements of array : ");
　　　for(i = 0; i < n;　++i) {
　　　　　　scanf("%d", p　+　i);
　　　　　　s　+=　*(p　+　i);
　　　}
　　　printf("\nSum : %d", s);
　　　return 0;
}

Output result

Enter elements of array :　2　28　12　32
Sum :　74

In the above C language example, if we perform an explicit cast, no error will be displayed.

The following is using C ++the syntax for allocating memory in the language.

pointer_name = (cast-type*) malloc(size);

Here,

pointer_name-to any name given to the pointer.

cast- type-to the data type that needs to be converted to allocate memory by forcemalloc().

Size-the size of memory allocated in bytes.

The following ismalloc()C ++language examples.

Example

#include <iostream>
using namespace std;
int main() {
　　　int n =　4, i,　*p, s = 0;
　　　p = (int　*)malloc(n　*　sizeof(int));
　　　if(p == NULL) {
　　　　　　cout << "\nError! memory not allocated.";
　　　　　　exit(0);
　　　}
　　　cout << "\nEnter elements of array : ";
　　　for(i = 0; i < n;　++i) {
　　　　　　cin >> (p　+　i);
　　　　　　s　+=　*(p　+　i);
　　　}
　　　cout << "\nSum : ", s;
　　　return 0;
}

Output result

Enter elements of array :　28　65　3　8
Sum :　104

In the above C ++In the language examples, if we do not perform an explicit conversion, the program will display the following error.

error: invalid conversion from ‘void*’ to ‘int*’ [-fpermissive]
p = malloc(n　*　sizeof(int));