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carraysrealloc

realloc an array of string

Currently, I have some confusion in realloc an array string. If I have this:

char** str = (char**)malloc(100*sizeof(char*));
str[0] = (char*)malloc(sizeof(char)*7); //allocate a space for string size 7
//some other code that make the array full

My question is, if I want to realloc str[0] to size 8, do I need to realloc both str and str[0] like this:

str = (char**)realloc(str,sizeof(char*)*101);
str[0] = (char*)realloc(str[0],sizeof(char)*8);

Is this correct?

Solution

  • You realloc the master array when you want to add a string (changing the number of strings). You realloc an individual string when you want to change that string's length.

    Therefore, only realloc str[0] if you want to change the string's buffer size.