In these days i'm playing with the C functions of atol(), atof() and atoi(), from a blog post i find a tutorial and applied:

here are my results:

void main()

char a[10],b[10];
puts("Enter the value of a");
gets(a);
puts("Enter the value of b");
gets(b);
printf("%s+%s=%ld and %s-%s=%ld",a,b,(atol(a)+atol(b)),a,b,(atol(a)-atol(b)));
getch();
}

there is atof() which returns the float value of the string and atoi() which returns integer value.

now to see the difference between the 3 i checked this code:

main()
{
char a[]={"2545.965"};
printf("atol=%ld\t atof=%f\t atoi=%d\t\n",atol(a),atof(a),atoi(a));
}

the output will be

atol=2545 atof=2545.965000 atoi=2545


char a[]={“heyyou”};

now when you run the program the following will be the output (why?, is there any solution to convert pure strings to integer?)

atol=0 atof=0 atoi=0

the string should contain numeric value now modify this program as

char a[]={“007hey”};

the output in this case(tested in Red hat) will be

atol=7 atof=7.000000 atoi=7

so the functions has taken 007 only not the remaining part (why?)

Now consider this

char a[]={“hey007?};

the output of the program will be

atol=0 atof=0.000000 atoi=0

So i just want to convert my strings to number and then again to same text, i played with these functions and as you see i'm getting really interesting results?

why is that?

any other functions to convert from/to string/integer and vice versa?