I have the following code.According to this the values of pointers p[0] and p[1] remains unchanged since the swap is made to local variables in swap function.Now my doubt is how can I swap the pointers p[0] and p[1] inside the function swap??
#include<stdio.h>
int main()
{
char *p[2]={"hello","good morning"};
swap(p[0],p[1]);
printf("%s %s",p[0],p[1]);
return 0;
}
void swap(char *a,char *b)
{
char *t;
t=a;
a=b;
b=t;
}
You will need to you double indirection, i.e., a pointer to a pointer.
#include<stdio.h>
void swap(char **a,char **b);
int main()
{
char *p[2]={"hello","good morning"};
swap(&p[0],&p[1]);
printf("%s %s",p[0],p[1]);
return 0;
}
void swap(char **a,char **b)
{
char *t;
t = *a;
*a = *b;
*b = t;
}
Not entirely obvious, but simple enough once you see it.
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