Insert element into dynamic char array in C programming -

i having problem when trying add element dynamic char array in c programming. here expected output:

how many characters want input: 5 input string:datas string is: datas want 1-insert or 2-remove or 3-quit?: 1 character want insert: resulting string: adata 

i did user input part in main function , here code in main take in string input, size , pass them insert():

printf("how many characters want input: "); scanf("%d", &n); str = malloc(n + 1); printf("input string class: "); scanf("%s", str);  case '1':     printf("what character want insert: ");     scanf(" %c", &input);     insert(str, input, n);     break; 

and part insert():

void insert(char *str, char input, int n) { int i; size_t space = 1; (i = 0; < n; i++) {     str[i] = (char)(input + i);     space++;                            str = realloc(str, space);      if (i > 2) {         break;     } }  (i = 0; < n; i++) {     printf("%c", str[i]); } } 

however, when tried print out string insert(), let's entered 'a' append first element of dynamic array size of 5, result getting abcd=

i referenced stackoverflow thread , not sure how fix this. in advance.

here code - contract caller free bit! caller calls insert(&str, input, n)

void insert(char **str, char input, int n) {  char* temp = *str; int i;  *str = realloc(*str, n + 2); /* realloc first */  if(!*str) /* realloc failed */ {     fputs("realloc failed", stderr);     free(temp); /* free malloc-ed memory */     exit(-1); /* exit program */ }  (i = n; >= 0; i--) {     (*str)[i + 1] = (*str)[i]; /* move characters */  }  (*str)[0] = input; /* insert new character */  printf("%s", *str); /* print new string */ } 

sorry formatting. left reader. have not checked algorithm not leak memory