Load the file lottypes.c and display it your screen.
main( )
{
int a; /* simple integer type */
long int b; /* long integer type */
short int c; /* short integer type */
unsigned int d; /* unsigned integer type */
char e; /* character type */
float f; /* floating point type */
double g; /* double precision floating point */
a = 1023;
b = 2222;
c = 123;
d = 1234;
e = ’X’;
f = 3.14159;
g = 3.1415926535898;
printf("a = %d\n",a); /* decimal output */
printf("a = %o\n",a); /* octal output */
printf("a = %x\n",a); /* hexadecimal output */
printf("b = %1d\n",b); /* decimal long output */
printf("c = %d\n",c); /* decimal short output */
printf("d = %u\n",d); /* unsigned output */
printf("e = %c\n",e); /* character output */
printf("f = %f\n",f); /* floating output */
printf("g = %f\n",g); /* double float output */
printf("\n");
printf("a = %d\n",a); /* simple int output */
printf("a = %7d\n",a); /* use a field width of 7 */
printf("a = %-7d\n",a); /* left justify in field of 7 */
printf("\n");
printf("f = %f\n",f); /* simple float output */
printf("f = %12f\n",f); /* use field width of 12 */
printf("f = %12.3f\n",f); /* use 3 decimal places */
printf("f = %12.5f\n",f); /* use 5 decimal places */
printf("f = %-12.5f\n",f); /* left justify in field */
}
This file contains every standard simple data type available in the programming language C. There are other types, but they are the compound types that we will cover in due time. Observe the file. First we define a simple "int" followed by a "long int" and a "short int". Consult your reference manual for an exact definition of these for your compiler, because they are not consistent from implementation to implementation. The "unsigned" is next and is defined as the same size as the "int" but with no sign. The "unsigned" then will cover a range of 0 to 65535 on MS-DOS microcomputers, but as 0 to 4294967296 in HiTech. It should be pointed out that when "long", "short", or "unsigned" is desired, the "int" is optional and left out by most experienced programmers. We have already covered the "char" and the "float", which leaves only the "double". The "double" usually covers a greater range than the "float" and has more significant digits for more precise calculations. It also requires more memory to store a value than the simple "float". Consult your referencemanual for the rangeand accuracy of the "double". Another diversion is in order at this point. Most compilers have provisions for floating point math, but only double floating math. They will promote a "float" to a "double" before doing calculations and therefore only one math library will be needed. Of course, this is totally transparent to you, so you don’t need to worry about it. You may think that it would be best to simply define every floating point variable as double, since they are promoted before use in any calculations, but that may not be a good idea. A "float" variable requires 4 bytes of storage and a "double" requires 8 bytes of storage, so if you have a large volume of floating point data to store, the "double" will obviously require much more memory. Your compiler may require a different number of bytes than 4 or 8. Consult your reference manual for the correct number of bytes used by your compiler.
After defining the data types, a numerical value is assigned to each of the defined variables in order to demonstrate the means of outputting each to the monitor.
main( )
{
int a; /* simple integer type */
long int b; /* long integer type */
short int c; /* short integer type */
unsigned int d; /* unsigned integer type */
char e; /* character type */
float f; /* floating point type */
double g; /* double precision floating point */
a = 1023;
b = 2222;
c = 123;
d = 1234;
e = ’X’;
f = 3.14159;
g = 3.1415926535898;
printf("a = %d\n",a); /* decimal output */
printf("a = %o\n",a); /* octal output */
printf("a = %x\n",a); /* hexadecimal output */
printf("b = %1d\n",b); /* decimal long output */
printf("c = %d\n",c); /* decimal short output */
printf("d = %u\n",d); /* unsigned output */
printf("e = %c\n",e); /* character output */
printf("f = %f\n",f); /* floating output */
printf("g = %f\n",g); /* double float output */
printf("\n");
printf("a = %d\n",a); /* simple int output */
printf("a = %7d\n",a); /* use a field width of 7 */
printf("a = %-7d\n",a); /* left justify in field of 7 */
printf("\n");
printf("f = %f\n",f); /* simple float output */
printf("f = %12f\n",f); /* use field width of 12 */
printf("f = %12.3f\n",f); /* use 3 decimal places */
printf("f = %12.5f\n",f); /* use 5 decimal places */
printf("f = %-12.5f\n",f); /* left justify in field */
}
This file contains every standard simple data type available in the programming language C. There are other types, but they are the compound types that we will cover in due time. Observe the file. First we define a simple "int" followed by a "long int" and a "short int". Consult your reference manual for an exact definition of these for your compiler, because they are not consistent from implementation to implementation. The "unsigned" is next and is defined as the same size as the "int" but with no sign. The "unsigned" then will cover a range of 0 to 65535 on MS-DOS microcomputers, but as 0 to 4294967296 in HiTech. It should be pointed out that when "long", "short", or "unsigned" is desired, the "int" is optional and left out by most experienced programmers. We have already covered the "char" and the "float", which leaves only the "double". The "double" usually covers a greater range than the "float" and has more significant digits for more precise calculations. It also requires more memory to store a value than the simple "float". Consult your referencemanual for the rangeand accuracy of the "double". Another diversion is in order at this point. Most compilers have provisions for floating point math, but only double floating math. They will promote a "float" to a "double" before doing calculations and therefore only one math library will be needed. Of course, this is totally transparent to you, so you don’t need to worry about it. You may think that it would be best to simply define every floating point variable as double, since they are promoted before use in any calculations, but that may not be a good idea. A "float" variable requires 4 bytes of storage and a "double" requires 8 bytes of storage, so if you have a large volume of floating point data to store, the "double" will obviously require much more memory. Your compiler may require a different number of bytes than 4 or 8. Consult your reference manual for the correct number of bytes used by your compiler.
After defining the data types, a numerical value is assigned to each of the defined variables in order to demonstrate the means of outputting each to the monitor.
