#include <stdio.h>
 
void cat_data(int *data1, const int *data2, int len2)
{
    int i = 0;
    int j = 0;
    while (i < 7 && data1[i] != 0) {
        i++;
    }
    while (i < 7 && j < len2) {
        data1[i] = data2[j];
        i++;
        j++;
    }
}
int main(void)
{
    int data1[7] = {1, 2, 0, 0, 0, 0, 0};
    int data2[5] = {3, 4, 5, 6, 7};
    int len2 = 5;
    cat_data(data1, data2, len2);
    for (int i = 0; i < 7; i++) {
        printf("data1[%d] = %d\n", i, data1[i]);
    }
    return 0;
}

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