How to change a character in a string using pointers?

Question

im having troubles with this code

int main() {
     char *My_St = "abcdef";
     *(My_St+1)='+';
     printf("%s\n",My_St);
     return 0;
}

i built this code and has no errors, but when i try to run it, it throws a segmentation fault, could someone tell what's wrong

Answer 1

You can't because you are trying to modify const data.

change it to:

char My_St[] = "abcdef";

Then you will be able to change it.

Think about what you were doing, you were declaring a pointer that pointed to "abcdef". It IS a pointer, not an array of chars. "abcdef" lives in the farm, I mean, in the .text area of your program and that is immutable.

When you do it the way I've shown, you are telling the compiler: i'm declaring this array, that will have as many chars as are needed to accommodate "abcdef" and also, as you are there, copy "abcdef" to it.