#include <stdio.h>
#define SIZE1 7
#define SIZE2 5
 
void cat_data(int *data1, int len1, int *size1, const int *data2, int len2) {
 
    int i;
    int remain = len1 - *size1; 
    int copy_len = (len2 < remain) ? len2 : remain; 
 
    for (i = 0; i < copy_len; i++) {
        data1[*size1 + i] = data2[i];
    }
    *size1 += copy_len; 
}
 
int main(void) {
    int data1[SIZE1] = {1, 2}; 
    int data2[SIZE2] = {3, 4, 5, 6, 7};
    int size1 = 2; 
 
    cat_data(data1, SIZE1, &size1, data2, SIZE2);
 
    for (int i = 0; i < size1; i++) {
        printf("data1[%d] = %d\n", i, data1[i]);
    }
 
    return 0;
}

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