1. C language variable type, global variable, local variable

Variable type

    char         1 byte

    short        2    2^16-1 = 65535

    int            4

    long         4/8

    float         4

    double     8  

    Setting the data type is in the Apply space to memory

Global and local variables

    Global variables : It's defined in Code block ({}) outside The variable of

    local variable : It's defined in Inside the code block

    It is suggested that the names of local variables should not be the same , If When the names are the same , Local variables take precedence

    C Language policy ： The variable should be defined at the front of the current code block .

int a = 100;// Global variables 
int main(int argc, char const *argv[])
{
    int a = 10;// local variable 
    printf("%d", a);
    return 0;
}