Compiler Error 70

Incomplete type is not allowed

main.cpp

#include "mbed.h"

DigitalOut myled(LED1);

int main() {
    char data[];     // <---- Incomplete type
    while(1) {
        myled = 1;
        wait(0.2);
        myled = 0;
        wait(0.2);
    }
}

The array cannot be defined without a size. You can specify the size like this

char data[5];

or

char data[] = {'a', 'b', 'c', 'd'};
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