Noise pollution is a significant environmental issue, particularly in industrial settings. The constant hum of machinery, the clanging of metal, and the roar of engines contribute to a cacophony that can have serious health implications for workers and nearby residents. Addressing noise pollution in industries is not only a matter of regulatory compliance but also a crucial step in ensuring the well-being of employees and the community. Understanding Noise Pollution in Industries Industrial noise pollution stems from various sources such as heavy machinery, generators, compressors, and transportation vehicles. Prolonged exposure to high levels of noise can lead to hearing loss, stress, sleep disturbances, and cardiovascular problems. Beyond health impacts, noise pollution can also reduce productivity, increase error rates, and contribute to workplace accidents. Regulatory Framework Many countries have established regulations and standards to limit industrial noise. Organizations like t
Pointer to Pointers
In C, you can also use pointers that point to pointers. The pointers in turn point to data or even to other pointers. To declare pointers to pointers, just add an asterisk * for each level of reference.
For example, consider the following code:
int x=10;
int *px, **ppx;
px = &x;
ppx = &px;
Let us assume, the memory locations of these variables are as shown in Fig.above
Now if we write,
printf("\n %d", **ppx);
Then, it would print 10, the value of x.
Drawbacks of Pointers
Although pointers are very useful in C, they are not free from limitations. If used incorrectly, pointers can lead to bugs that are difficult to unearth. For example, if you use a pointer to read a memory location but that pointer is pointing to an incorrect location, then you may end up reading
a wrong value. An erroneous input always leads to an erroneous output. Thus however efficient your program code may be, the output will always be disastrous. Same is the case when writing a value to a particular memory location.
Let us try to find some common errors when using pointers.
int x, *px;
x=10;
*px = 20;
Error: Un-initialized pointer. px is pointing to an unknown memory location. Hence it willoverwrite that location’s contents and store 20 in it.
int x, *px;
x=10;
px = x;
Error: It should be px = &x;
int x=10, y=20, *px, *py;
px = &x, py = &y;
if(px<py)
printf("\n x is less than y");
else
printf("\n y is less than x");
Error: It should be if(*px< *py)