Home » Archimedes archive » Acorn User » AU 1995-02.adf » !C_c » c/Arithmetic
c/Arithmetic
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| Tape/disk: | Home » Archimedes archive » Acorn User » AU 1995-02.adf » !C_c |
| Filename: | c/Arithmetic |
| Read OK: | ✔ |
| File size: | 056E bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
/* Program arithmetic: a contrived example of functions in C */
#include <stdio.h>
/* The variable �error� is defined outside any functions, at the lowest */
/* brace level. This means that it is visible to all the functions in */
/* the program. Here it is used as an error indicator to flag a �divide */
/* by zero error on the divide() function. */
char error = 'n';
int add(int x, int y)
{ int result;
result = x+y;
return result;
}
int subtract(int x, int y)
{ int result;
result = x-y;
return result;
}
int multiply(int x, int y)
{ return x*y ;
}
double divide(int x, int y)
{ if (y == 0)
{ error = 'z';
return 0;
}
return (double)x/(double)y;
}
main()
{ int arg1, arg2, sum, difference, product;
double dividend;
do
{ printf("Enter two numbers\n");
scanf("%d %d", &arg1, &arg2);
while (getchar() != '\n') ;
sum = add(arg1, arg2);
difference = subtract(arg1, arg2);
product = multiply(arg1, arg2);
dividend = divide(arg1, arg2);
printf("%d + %d = %d\n", arg1, arg2, sum);
printf("%d - %d = %d\n", arg1, arg2, difference);
printf("%d � %d = %d\n", arg1, arg2, product);
if (error == 'z')
{ error = 'n';
printf("Division by zero: undefined result\n");
} else
{ printf("%d � %d = %f\n", arg1, arg2, dividend);
}
}
while((arg1!=0) || (arg2!=0));
return 0;
} 00000000 2f 2a 20 50 72 6f 67 72 61 6d 20 61 72 69 74 68 |/* Program arith|
00000010 6d 65 74 69 63 3a 20 61 20 63 6f 6e 74 72 69 76 |metic: a contriv|
00000020 65 64 20 65 78 61 6d 70 6c 65 20 6f 66 20 66 75 |ed example of fu|
00000030 6e 63 74 69 6f 6e 73 20 69 6e 20 43 20 2a 2f 0a |nctions in C */.|
00000040 0a 23 69 6e 63 6c 75 64 65 20 3c 73 74 64 69 6f |.#include <stdio|
00000050 2e 68 3e 0a 0a 2f 2a 20 54 68 65 20 76 61 72 69 |.h>../* The vari|
00000060 61 62 6c 65 20 90 65 72 72 6f 72 91 20 69 73 20 |able .error. is |
00000070 64 65 66 69 6e 65 64 20 6f 75 74 73 69 64 65 20 |defined outside |
00000080 61 6e 79 20 66 75 6e 63 74 69 6f 6e 73 2c 20 61 |any functions, a|
00000090 74 20 74 68 65 20 6c 6f 77 65 73 74 20 2a 2f 0a |t the lowest */.|
000000a0 2f 2a 20 62 72 61 63 65 20 6c 65 76 65 6c 2e 20 |/* brace level. |
000000b0 54 68 69 73 20 6d 65 61 6e 73 20 74 68 61 74 20 |This means that |
000000c0 69 74 20 69 73 20 76 69 73 69 62 6c 65 20 74 6f |it is visible to|
000000d0 20 61 6c 6c 20 74 68 65 20 66 75 6e 63 74 69 6f | all the functio|
000000e0 6e 73 20 69 6e 20 20 20 2a 2f 0a 2f 2a 20 74 68 |ns in */./* th|
000000f0 65 20 70 72 6f 67 72 61 6d 2e 20 48 65 72 65 20 |e program. Here |
00000100 69 74 20 69 73 20 75 73 65 64 20 61 73 20 61 6e |it is used as an|
00000110 20 65 72 72 6f 72 20 69 6e 64 69 63 61 74 6f 72 | error indicator|
00000120 20 74 6f 20 66 6c 61 67 20 61 20 90 64 69 76 69 | to flag a .divi|
00000130 64 65 20 2a 2f 0a 2f 2a 20 62 79 20 7a 65 72 6f |de */./* by zero|
00000140 20 65 72 72 6f 72 20 6f 6e 20 74 68 65 20 64 69 | error on the di|
00000150 76 69 64 65 28 29 20 66 75 6e 63 74 69 6f 6e 2e |vide() function.|
00000160 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | |
00000170 20 20 20 20 20 20 20 20 20 20 20 20 20 20 2a 2f | */|
00000180 0a 0a 63 68 61 72 20 65 72 72 6f 72 20 3d 20 27 |..char error = '|
00000190 6e 27 3b 0a 0a 69 6e 74 20 61 64 64 28 69 6e 74 |n';..int add(int|
000001a0 20 78 2c 20 69 6e 74 20 79 29 0a 7b 20 69 6e 74 | x, int y).{ int|
000001b0 20 72 65 73 75 6c 74 3b 0a 20 20 72 65 73 75 6c | result;. resul|
000001c0 74 20 3d 20 78 2b 79 3b 0a 20 20 72 65 74 75 72 |t = x+y;. retur|
000001d0 6e 20 72 65 73 75 6c 74 3b 0a 7d 0a 0a 69 6e 74 |n result;.}..int|
000001e0 20 73 75 62 74 72 61 63 74 28 69 6e 74 20 78 2c | subtract(int x,|
000001f0 20 69 6e 74 20 79 29 0a 7b 20 69 6e 74 20 72 65 | int y).{ int re|
00000200 73 75 6c 74 3b 0a 20 20 72 65 73 75 6c 74 20 3d |sult;. result =|
00000210 20 78 2d 79 3b 0a 20 20 72 65 74 75 72 6e 20 72 | x-y;. return r|
00000220 65 73 75 6c 74 3b 0a 7d 0a 0a 69 6e 74 20 6d 75 |esult;.}..int mu|
00000230 6c 74 69 70 6c 79 28 69 6e 74 20 78 2c 20 69 6e |ltiply(int x, in|
00000240 74 20 79 29 0a 7b 20 72 65 74 75 72 6e 20 78 2a |t y).{ return x*|
00000250 79 20 3b 0a 7d 0a 0a 64 6f 75 62 6c 65 20 64 69 |y ;.}..double di|
00000260 76 69 64 65 28 69 6e 74 20 78 2c 20 69 6e 74 20 |vide(int x, int |
00000270 79 29 0a 7b 20 69 66 20 28 79 20 3d 3d 20 30 29 |y).{ if (y == 0)|
00000280 0a 20 20 7b 20 65 72 72 6f 72 20 3d 20 27 7a 27 |. { error = 'z'|
00000290 3b 0a 20 20 20 20 72 65 74 75 72 6e 20 30 3b 0a |;. return 0;.|
000002a0 20 20 7d 0a 20 20 72 65 74 75 72 6e 20 28 64 6f | }. return (do|
000002b0 75 62 6c 65 29 78 2f 28 64 6f 75 62 6c 65 29 79 |uble)x/(double)y|
000002c0 3b 0a 7d 0a 0a 6d 61 69 6e 28 29 0a 7b 20 69 6e |;.}..main().{ in|
000002d0 74 20 61 72 67 31 2c 20 61 72 67 32 2c 20 73 75 |t arg1, arg2, su|
000002e0 6d 2c 20 64 69 66 66 65 72 65 6e 63 65 2c 20 70 |m, difference, p|
000002f0 72 6f 64 75 63 74 3b 0a 20 20 64 6f 75 62 6c 65 |roduct;. double|
00000300 20 64 69 76 69 64 65 6e 64 3b 0a 20 20 64 6f 0a | dividend;. do.|
00000310 20 20 7b 20 70 72 69 6e 74 66 28 22 45 6e 74 65 | { printf("Ente|
00000320 72 20 74 77 6f 20 6e 75 6d 62 65 72 73 5c 6e 22 |r two numbers\n"|
00000330 29 3b 0a 20 20 20 20 73 63 61 6e 66 28 22 25 64 |);. scanf("%d|
00000340 20 25 64 22 2c 20 26 61 72 67 31 2c 20 26 61 72 | %d", &arg1, &ar|
00000350 67 32 29 3b 0a 20 20 20 20 77 68 69 6c 65 20 28 |g2);. while (|
00000360 67 65 74 63 68 61 72 28 29 20 21 3d 20 27 5c 6e |getchar() != '\n|
00000370 27 29 20 3b 0a 20 20 20 20 73 75 6d 20 3d 20 61 |') ;. sum = a|
00000380 64 64 28 61 72 67 31 2c 20 61 72 67 32 29 3b 0a |dd(arg1, arg2);.|
00000390 20 20 20 20 64 69 66 66 65 72 65 6e 63 65 20 3d | difference =|
000003a0 20 73 75 62 74 72 61 63 74 28 61 72 67 31 2c 20 | subtract(arg1, |
000003b0 61 72 67 32 29 3b 0a 20 20 20 20 70 72 6f 64 75 |arg2);. produ|
000003c0 63 74 20 3d 20 6d 75 6c 74 69 70 6c 79 28 61 72 |ct = multiply(ar|
000003d0 67 31 2c 20 61 72 67 32 29 3b 0a 20 20 20 20 64 |g1, arg2);. d|
000003e0 69 76 69 64 65 6e 64 20 3d 20 64 69 76 69 64 65 |ividend = divide|
000003f0 28 61 72 67 31 2c 20 61 72 67 32 29 3b 0a 20 20 |(arg1, arg2);. |
00000400 20 20 70 72 69 6e 74 66 28 22 25 64 20 2b 20 25 | printf("%d + %|
00000410 64 20 3d 20 25 64 5c 6e 22 2c 20 61 72 67 31 2c |d = %d\n", arg1,|
00000420 20 61 72 67 32 2c 20 73 75 6d 29 3b 0a 20 20 20 | arg2, sum);. |
00000430 20 70 72 69 6e 74 66 28 22 25 64 20 2d 20 25 64 | printf("%d - %d|
00000440 20 3d 20 25 64 5c 6e 22 2c 20 61 72 67 31 2c 20 | = %d\n", arg1, |
00000450 61 72 67 32 2c 20 64 69 66 66 65 72 65 6e 63 65 |arg2, difference|
00000460 29 3b 0a 20 20 20 20 70 72 69 6e 74 66 28 22 25 |);. printf("%|
00000470 64 20 d7 20 25 64 20 3d 20 25 64 5c 6e 22 2c 20 |d . %d = %d\n", |
00000480 61 72 67 31 2c 20 61 72 67 32 2c 20 70 72 6f 64 |arg1, arg2, prod|
00000490 75 63 74 29 3b 0a 20 20 20 20 69 66 20 28 65 72 |uct);. if (er|
000004a0 72 6f 72 20 3d 3d 20 27 7a 27 29 0a 20 20 20 20 |ror == 'z'). |
000004b0 7b 20 65 72 72 6f 72 20 3d 20 27 6e 27 3b 0a 20 |{ error = 'n';. |
000004c0 20 20 20 20 20 70 72 69 6e 74 66 28 22 44 69 76 | printf("Div|
000004d0 69 73 69 6f 6e 20 62 79 20 7a 65 72 6f 3a 20 75 |ision by zero: u|
000004e0 6e 64 65 66 69 6e 65 64 20 72 65 73 75 6c 74 5c |ndefined result\|
000004f0 6e 22 29 3b 0a 20 20 20 20 7d 20 65 6c 73 65 0a |n");. } else.|
00000500 20 20 20 20 7b 20 70 72 69 6e 74 66 28 22 25 64 | { printf("%d|
00000510 20 f7 20 25 64 20 3d 20 25 66 5c 6e 22 2c 20 61 | . %d = %f\n", a|
00000520 72 67 31 2c 20 61 72 67 32 2c 20 64 69 76 69 64 |rg1, arg2, divid|
00000530 65 6e 64 29 3b 0a 20 20 20 20 7d 0a 20 20 7d 0a |end);. }. }.|
00000540 20 20 77 68 69 6c 65 28 28 61 72 67 31 21 3d 30 | while((arg1!=0|
00000550 29 20 7c 7c 20 28 61 72 67 32 21 3d 30 29 29 3b |) || (arg2!=0));|
00000560 0a 20 20 72 65 74 75 72 6e 20 30 3b 0a 7d |. return 0;.}|
0000056e 
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