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Return pointer from functions in C
We have seen in the last chapter how C programming allows to return an array from a function. Similarly, C also allows to return a pointer from a function. To do so, you would have to declare a function returning a pointer as in the following example −
int * myFunction() { . . . }
Second point to remember is that, it is not a good idea to return the address of a local variable outside the function, so you would have to define the local variable as static variable.
Now, consider the following function which will generate 10 random numbers and return them using an array name which represents a pointer, i.e., address of first array element.
#include <stdio.h> #include <time.h> /* function to generate and return random numbers. */ int * getRandom( ) { static int r[10]; int i; /* set the seed */ srand( (unsigned)time( NULL ) ); for ( i = 0; i < 10; ++i) { r[i] = rand(); printf("%d\n", r[i] ); } return r; } /* main function to call above defined function */ int main () { /* a pointer to an int */ int *p; int i; p = getRandom(); for ( i = 0; i < 10; i++ ) { printf("*(p + [%d]) : %d\n", i, *(p + i) ); } return 0; }
When the above code is compiled together and executed, it produces the following result −
1523198053 1187214107 1108300978 430494959 1421301276 930971084 123250484 106932140 1604461820 149169022 *(p + [0]) : 1523198053 *(p + [1]) : 1187214107 *(p + [2]) : 1108300978 *(p + [3]) : 430494959 *(p + [4]) : 1421301276 *(p + [5]) : 930971084 *(p + [6]) : 123250484 *(p + [7]) : 106932140 *(p + [8]) : 1604461820 *(p + [9]) : 149169022
c_pointers.htm
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