how to assign value to pointer string in C -

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in c language trying assign value pointer string. cannot use char array, have use pointer string. please tell how can that?

i doing (code given), when run code error prompted program stopped working.

#include <stdio.h>   int main (void) {      char *mystring = " ";     int value = 1;      mystring[0] = value+'0';      printf("%s\n",mystring);      return 0; } 

you cannot modify string literal: mystring initialized point constant storage string literal. attempting modify invokes undefined behavior. use strdup() create copy of string:

#include <stdio.h> #include <string.h>  int main(void) {     char *mystring = strdup(" ");     int value = 1;      mystring[0] = value + '0';      printf("%s\n", mystring);      free(mystring);      return 0; } 

strdup() function standardized in posix, allocates block of memory heap long enough receive copy of string argument. copies string , returns pointer block. such block can modified, , should freed free() when no longer needed.