将结构数组复制到 C 中的另一个（非结构）数组

Question

I am trying to copy name array to another array and print it

#include <stdio.h>

typedef struct 
{
    char name[100];
    int age;
} data; 

int main() {
    char new_array[100];
    data people[] = {{ "john", 12},{" kate", 15}};
    for(int i =0; i < sizeof(people); i++) {
        new_array[i] = people[i].name;
        printf("%c ", new_array[i]);
    }

    return 0;
}

But it gives me an error:

error: assignment to ‘char’ from ‘char *’ makes integer from pointer without a cast [-Werror=int-conversion]
     new_array[i] = people[i].name;
                  ^

How do I fix this?

Answer 1

You can change:

char new_array[100];

to:

char new_array[10][100]; // for maximum 10 strings

Then using strcpy to copy string in c. If you want to calculate the number of elements of array, using:

sizeof(people)/sizeof(people[0]);

Then, the for loop becomes:

for(int i =0; i < sizeof(people)/sizeof(people[0]); i++) {
        strcpy(new_array[i],people[i].name);
        printf("%s ", new_array[i]);
}

Answer 2

You are trying to assign a string to a char which is described by your error. To copy a string to a char array, you should use strcpy() .

Also, your new_array is a mere array of characters and has no way to differentiate two different names.

To make it an array of strings, you should use a 2D array where you can index the row to get different strings like below

char new_array[10][100]

This makes an array of 10 strings of 100 characters each.

Also, your iteration over the array of structure is messy.

To get correct size of array of structure, you should use

int size = sizeof(people)/sizeof(people[0])

So, your final code becomes-

#include <stdio.h>
#include <string.h>

typedef struct 
{
    char name[100];
    int age;
} data; 

int main() {
    char new_array[10][100];
    data people[] = {{ "john", 12},{" kate", 15}};
    for(int i =0; i < sizeof(people)/sizeof(people[0]); i++) {
        strcpy(new_array[i],people[i].name);
        printf("%s ", new_array[i]);
    }

    return 0;
}