hello , real problem

[khalilshawahin]

my teacher want to write code in argument like this

#include <iostream>
using namespace std ;
int main (int argc , char* argv[])

{
int x=0 , y=0;
x=argv[1][0] - '0';
y=argv[2][0] - '0';
cout << "sum = "<< x+y <<endl;
return 0 ;
}

then g++ myfil.cpp -o my
./ 123 5

now i have aproblem because the program just read one digit .
please i need an answer ...

thanks

[shadow123]

#include <iostream>
#include <cstdlib>
using namespace std ;
int main (int argc , char* argv[])

{
int x=0 , y=0;
x=atoi(argv[1]);
y=atoi(argv[2]);
cout << "sum = "<< x+y <<endl;
return 0 ;
}

atoi = http://www.cplusplus.com/reference/clibrary/cstdlib/atoi/
You should check if argc >= 3.

[khalilshawahin]

how can i check argc ,

is atoi do it alone ?

[shadow123]

how can i check argc ,

#include <iostream>
#include <cstdlib>
using namespace std ;
int main (int argc , char* argv[])

{


if(argc != 3) {
cerr << "we need exactly two numeric arguments!" << endl;
return -1;
}

int x=0 , y=0;
x=atoi(argv[1]);
y=atoi(argv[2]);
cout << "sum = "<< x+y <<endl;
return 0 ;
}

something like that...

is atoi do it alone

atoi is a function in the c/c++ standard library. this function converts a numerical string into an integer, so you are able to do numerical operations with it.

[khalilshawahin]

shadow ,

did you understand my question ?

i am coding in c++ under linux by arguments

#include <cstdlib>
#include <iostream>

using namespace std;

int main(int argc, char *argv[])
{
    
    int , x=0 , y=0 ,z=0;
    x=argv[1][0]-'0';
    y=argv[2][0]-'0';
            cout<<" sum =  "<<x+y<<endl;
    
    return 0;
}

for example the file name k.cpp

i do this

g++ k.cpp -o k
./k 4 5

the output will be 9 ,

but if i write like this

./k 122 5

will be an error ,

" i need if i write this ./k 122 5 the output will be 127 " -> that is the problem .

thanks

[S G H]

He answered you. That's a good answer, even.

[kooth]

They are both right: You are going to need atoi to get any number with more than one character in it using the argument vectors the way you are.