The calculation of large integers can be simplified through modular operations, or they can be read in as strings and then concatenated after segmented operations.

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The sample codes for atoi and itoa are as follows:

#include

#include

void main( void )

{

char *s; int ix;

char buffer[20];< /p>

int i = 3445;

long l = -344115L;

unsigned long ul = 1234567890UL;

s = " -9885 pigs "; /* Test of atoi */

ix = atoi( s );

printf( "atoi test: ASCII string: %s\t\tinteger: %d\n ", s, ix );

_itoa( i, buffer, 10);

printf( "String of integer %d (radix 10): %s\n", i , buffer );

_itoa( i, buffer, 16 );

printf( "String of integer %d (radix 16): 0x%s\n", i, buffer );

_itoa( i, buffer, 2 );

printf( "String of integer %d (radix 2): %s\n", i, buffer );< /p>

_ltoa( l, buffer, 16 );

printf( "String of long int %ld (radix 16): 0x%s\n", l,

_ultoa( ul, buffer, 16 );

printf( "String of unsigned long %lu (radix 16): 0x%s\n", ul ,

buffer );

}

Output result:

atoi test: ASCII string: -9885 pigs integer: -9885< /p>

String of integer 3445 (radix 10): 3445

String of integer 3445 (radix 16): 0xd75

String of integer 3445 (radix 2): 110101110101

String of long int -344115 (radix 16): 0xfffabfcd

String of unsigned long 1234567890 (radix 16): 0x499602d2