Shell Programming and Scripting

range=100;
echo "$range"

 int main() 
 { cout << range << "\n"; }

int main(int argc, char *argv[])
{   cout << range << "\n"; }

export range=100

#include <stdlib.h>

int main(int argc, char *argv[])
{
       const char *range=getenv("range");

        if(range == NULL)
        {
                cout << "Range not available\n";
        }
        else
        {
                cout << "Range is " << range << "\n";
        }

        return(0);
}

myprogram $range

int main(int argc, char *argv[])
{
        if(argc < 2)
        {
                cout << "No argument\n";
                return(1);
        }

        cout << "First argument " << argv[1] << "\n";
        return(0);
}

In function 'int main(int, char**)':
test_file.cpp:24: error: invalid operands of types 'const char*' and 'int' to binary 'operator*'

int range_m = range*1000;

error: invalid operands of types 'const char*' and 'int' to binary 'operator*'

int range_m = atoi(range)*1000;

int range_m;
sscanf(range, "%d", &range_m);
range_m *= 1000;