C program to reverse a string using pointers

‪#‎include‬<stdio.h>

int string_length(char*);
void reverse(char*);

main()
{
char string[100];

printf("Enter a string\n");
gets(string);

reverse(string);

printf("Reverse of entered string is \"%s\".\n", string);

return 0;
}

void reverse(char *string)
{
int length, c;
char *begin, *end, temp;

length = string_length(string);
begin = string;
end = string;

for (c = 0; c < length - 1; c++)
end++;

for (c = 0; c < length/2; c++)
{
temp = *end;
*end = *begin;
*begin = temp;

begin++;
end--;
}
}

int string_length(char *pointer)
{
int c = 0;

while( *(pointer + c) != '\0' )
c++;

return c;
}