I want to check if the string SET_NAME is the name of an existing set, and if so, SET1 will point to the address of that set.

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
typedef unsigned char set[16];

int main(){

    char set_name[5] = {'0'};
    char *set1;
    int i;

    set_name[0] = 'S';
    set_name[1] = 'E';
    set_name[2] = 'T';
    set_name[3] = 'B';

    set SETA = {'0'};
    set SETB = {'0'};
    set SETC = {'0'};
    set SETD = {'0'};
    
    struct{
        char *name;
        set *myset;
    }sets[]={
    {"SETA", &SETA}, 
    {"SETB", &SETB},
    {"SETC", &SETC},
    {"SETD", &SETD}
    };  
    
    for(i=0; i < 4;i  ){
        if(strcmp(set_name, sets[i].name)==0){
            set1 = sets[i].myset;
            printf("the set is found!\n%s\n", set_name);
        }
    }
    return 0;
}

This code does not work, probably due to incorrect use of elements in the structure. The compiler writes to me like this: assignment from incompatible pointer type [-Wincompatible-pointer-types] set1 = sets[i].myset; and also- warning: initializer element is not computable at load time [-Wpedantic] {"SETD", &SETD}, for each element in the array. I'm trying to fix and don't understand where my error is.

CodePudding user response：

1. Never hide arrays or pointers behind typedefs
2. Your string set_name is too short. It has to be 5 characters long to accommodate null terminating character as well
3. set_name[0] = {'S'}; makes no sense. If you want to assign a char to the particular element of the array do not use brackets.
4. set SETA = {'0'}; it will initialize SETA with character '0' as a first element and zeroes the rest.
5. &SETA has the wrong type (pointer to array of 16 chars, not pointer to char)

After some amendments:

#define SETLENGTH 16

int main(){

    char set_name[] = "SETB";
    char *set1;
    int i;

    char SETA[SETLENGTH] = "";
    char SETB[SETLENGTH] = "";    
    char SETC[SETLENGTH] = "";    
    char SETD[SETLENGTH] = "";    

    struct{
        char *name;
        char *myset;
    }sets[]={
    {"SETA", SETA}, 
    {"SETB", SETB},
    {"SETC", SETC},
    {"SETD", SETD}
    };  
    
    for(i=0; i < 4;i  ){
        if(strcmp(set_name, sets[i].name)==0){
            set1 = sets[i].myset;
            printf("the set is found!\n%s\n", set_name);
        }
    }
    return 0;
}