c - error convert character in string to uppercase -

i'm trying convert character of string uppercase letters

int main (void) {     int = 0;     int n = 0;     static char *str[] = { "wow",                            "racecar",                             "no devil lived on.",                            "rotor" };      for(i = 0; < strlen(*str); i++)     {         if(str[i] != null)         {             n = function(str[i]);         }     }     return 0; }  int function(char* x) {    int = 0;    int j = strlen(x);    char c;    for(i = 0; < j; i++)    {       c = toupper(x[i]);       x[i] = c;    }     return 0; } 

i got error saying exc bad access, code 2 @ line x[i] = c; i'm not sure why error, need create string , assign c new string? toupper return uppercase version of character didnt change element itself, i'm not sure wrong assigning value return toupper element.

your code attempts modify string literal , causes undefined behaviour.

the string "no devil lived on." non-modifiable. compiler catch error should declare array as:

static char const *str[] = { "wow", // etc. 

for historical reasons, compiler has let pass without breaking compilation if forget include const. still error nonetheless, , compilers warn anyway.

for gcc can use flag -wwrite-strings disable support historical case; cause error message generated code as-is.