Thread: C pointer assignment going awry

Hello all,

I'm trying to create a simple routine where I transform the individual characters of a character string to uppercase. I'm trying to figure out why I can dereference individual elements, but can't assign to them. I must be committing some fundamental mistake, but my book pretty much has the same logic I'm using. Any hints? Thanks in advance, as usual!

Code:

#include<stdio.h>
#include<ctype.h>
#include<string.h>

int main(void){
	char *c = "hello!";
	int i;
	for( i = 0; *(c+i) != '\0'; i++){
				if(islower(*(c+i))){
				*(c+i) = toupper(*(c+i));  //boom!  Why?
				}
	}

}