#include <stdio.h>
int main(int argc, char *argv[])
{
int a,b,sum;
if(argc!=3)
{
printf("please use \"prg_name value1 value2 \"\n");
return -1;
}
a = atoi(argv[1]);
b = atoi(argv[2]);
sum = a+b;
printf("Sum of %d, %d is: %d\n",a,b,sum);
return 0;
}First run:
sh-4.2$ ./main 10 20
Sum of 10, 20 is: 30
Second run:
sh-4.2$ ./main 10 20 30 40
please use "prg_name value1 value2 "
As we have discussed in command line argument tutorial, that we can also give the input to the program through the command line.
In this program, we will provide the input (two integer values) through the command line and program will add them and print the value of input numbers along with the sum of them.
Sample input
./main 10 20
Here, ./main is the program's executable file name, 10 and 20 are the input values.
Sample output
Sum of 10, 20 is: 30
atoi() is a library function that converts string to integer, when program gets the input from command line, string values transfer in the program, we have to convert them to integers (in this program). atoi() is used to return the integer of the string arguments.
First read the algorithm, then study the program code line by line. After that, compare the code with the output and finally go through the explanation. This approach helps learners understand both the logic and the implementation properly.
After understanding this example, try to rewrite the same program without looking at the code. Then change some values or logic and run it again. This helps improve confidence and keeps learners engaged on the page for longer.